The stock, which debuted at $26 in November, hit a low of $50 in early trading. The shares hit a peak of $74.73 in late December as investors bet that the social media platform could become as ubiquitous as Facebook.

Analysts, unlike investors, were divided on the company's outlook a day after it reported fourth-quarter results.

Twitter, according to broker assessments, is either the overvalued owner of a niche product whose potential is fading or an undervalued phenomenon that is set to give Facebook a run for its money in mobile.

"We remain firmly in the latter camp..." said Deutsche Bank, one of one at least six brokerages that raised target prices or ratings on Twitter's stock.

Deutsche, in a note entitled "Great Quarter, Aside From The Most Important Metric", said it was impressed by Twitter's improving monetization and expected slowing user growth to reverse during 2014.

The broker, which sees Twitter on its way to 1 billion user, maintained a "buy" rating on the stock and raised its price target to $65 from $50.

Facebook has about 1.2 billion users.

UBS, on the other side of the argument, issued a "sell" recommendation on the stock and cut its price target to $42 from $45. It was one of at least eight brokerages to cut their target prices or recommendations on Twitter's shares.

"A lack of mainstream adoption or a more simplified use case was a worry of ours coming out of the IPO and seems to have come to the fore faster than we had anticipated," UBS analyst Eric Sheridan said in a note.

Twitter reported better-than-expected fourth-quarter revenue of $243 million in its first results since the IPO.

Investors, however, zeroed in on the anemic user growth, as well as a sharp decline in a measure of user engagement.

Twitter averaged 241 million monthly users in the December quarter, up just 3.8 percent from the previous three months. That was the lowest rate of quarter-on-quarter growth since the company began disclosing user figures.

But the company also said it made $1.49 per 1,000 timeline views, a 76 percent jump from the same quarter of 2012.

"We believe the accelerating user growth and engagement, supplemented by improvements in monetization, will drive continued financial outperformance in the year ahead," Goldman Sachs analysts said in a note.

Twitter reported better-than-expected fourth-quarter revenue of $243 million in its first results since the IPO.

But the poet and playwright TS Eliot had a different take. “It is a medium of entertainment which permits millions of people to listen to the same joke at the same time, and yet remain lonesome,” he wrote.

Eliot and the others were writing about television in the early 1960s. But fast forward 50 years and you could be forgiven for thinking that their comments apply equally well to the internet, and online social networks.

Chief among these is Facebook, the social network that celebrates its 10th birthday this week. Its statistics are astounding. In just one decade, it has signed up some 1.3 billion people, half of whom log in on any given day and spend an average of 18 minutes per visit. Facebook connects families across continents, friends across the years and people around the world.

And yet Facebook’s effects on its users may not be entirely benign. Some researchers suggest that the ability to connect does not necessarily make people any happier, and it could in fact reduce the satisfaction they feel about their life. Can it really be possible that Facebook makes you sad?

Until recently, few had studied this question and the little evidence that did exist actually hinted that the social network has a beneficial effect. In 2009, Sebastian Valenzuela and colleagues at the University of Texas at Austin measured how life satisfaction varied among over 2,500 students who used Facebook, and they found a small positive correlation.

Yet last summer, a team of psychologists from the University of Michigan in Ann Arbor and the University of Leuven in Belgium decided to drill a bit deeper by evaluating how life satisfaction changes over time with Facebook use. Ethan Kross and colleagues questioned a group of people five times a day over two weeks about their emotional state.

They asked questions such as “how do you feel right now?”, “how lonely do you feel right now?”, “how much have you used Facebook since we last asked?” and so on. This gave them a snapshot of each individual’s well-being and Facebook usage throughout the day.

AOL's shares advanced 6 percent to $50.59 in morning trade after the results were released.

The company, which is trying to rely less on its declining dial-up subscription service, has turned its focus to reap more advertising dollars from brands.

That involves targeting three areas of growth in digital advertising: video, mobile and "programmatic" buying, where machines buy and sell advertising on electronic exchanges.

"The investments we have made are paying off," Tim Armstrong, AOL CEO said in an interview.

Advertising revenue soared 23 percent to $507 million on strong growth at its third party network, which includes its recent acquisition of video advertising platform Adap.tv.

AOL bought Adap.tv for $405 million last year.

That compares with Yahoo - AOL's most direct competitor - which turned in a bruising fourth quarter. Yahoo's revenue from display advertising fell 6 percent on lower priced ads.

"Tim is a year ahead of the market in terms of strategic decisions," said Laura Martin, an analyst with Needham & Co, who noted that Armstrong turned to programmatic buying earlier than its rivals.

AOL said its Brand Group, which includes media properties like The Huffington Post and TechCrunch, had increased its adjusted operating income before depreciation and amortization (OIBDA) to $35.6 million in the quarter, from $8.8 million in the same quarter last year. That is partly because of deep cuts at its hyperlocal network of neighborhood websites Patch. AOL handed majority ownership of Patch to turnaround firm Hale Global in January.

The company's total revenue was $679 million in the fourth quarter beating analysts' forecast of $655.8 million, according to Thomson Reuters I/B/E/S.

Net income attributable to AOL rose to $36 million, or 43 cents per share, in the quarter from $35.7 million, or 41 cents per share, a year earlier.

Better agriculture, education and health are just three of the improvements the system could bring, said the firm.

Watson uses artificial intelligence to analyse huge amounts of data and can also understand human language.

Experts said such a system could help the African economy "leapfrog" others.

The project dubbed, Lucy, after the earliest known human ancestor fossil which was found in east Africa, will cost $100m (£61m) and take 10 years to complete.

Uyi Stewart, chief scientist of IBM Research in Africa, told the BBC that the system could transform education and health in the same way as mobile banking had transformed finance on the continent.

"With the adoption of mobile phones, banking has become virtual and it could be the same premise in education and healthcare," he said.

Its ability to crunch through vast amounts of data and its access to a wealth of information could prove helpful in a variety of contexts.

And people will be able to ask it questions.

"It is also able to reason. One if its key functions is natural language processing," said Mr Stewart.

Schools with poor or non-existent computer resources could link into the cloud-based system via smartphones or portable devices with internet connectivity.

Doctors, nurses and field workers could use the system to help diagnose illnesses and identify the best treatment for each patient. So, for example, Watson could help answer why sub-Saharan Africa currently accounts for 22% of all cervical cancers. It could suggest new ways to treat and prevent the disease.

And analytics on the state of country roads and congestion levels in cities could prove useful for logistics firms that currently have to negotiate pothole-filled roads and traffic chaos.

A delivery firm in Lagos is already using the system to improve delivery times and schedules.

IBM is working on ways to make sure that Watson is able to provide relevant bite-sized chunks of information.

Prof Rahamon Bello, vice-chancellor of the university of Lagos, is excited by the prospect of access to a supercomputer which he thinks could help Africa "leapfrog other economies". Clever data mining has already proved its worth in Morocco where it has been used to improve how crops are grown by predicting weather, demand and disease outbreaks.

Despite the huge potential of artificial intelligence machines, IBM has made just $100m from Watson in the past three years.

State-controlled VTB bought Tele2 Russia from Nordic telecoms group Tele2 for $3.6 billion last April.

It later agreed to sell half of the business to a group of investors including affiliates of Bank Rossiya and entities of Alexei Mordashov, a billionaire tycoon who controls steelmaker Severstal.

And last year, Tele2 Russia, already the country's No.4 mobile operator, decided to merge with the wireless assets of Rostelecom, aiming to close the gap on MTS, Megafon and Vimpelcom which together control more than 80 percent of the Russian mobile market.

"This is a strategic project for us and a relatively long-term investment for all the shareholders. The minimum term we are looking at to develop the company is likely three years," said Yuri Soloviev, VTB's First Deputy President, as the two operators signed a framework agreement to press ahead with the merger.

The bank may then exit T2 RTK Holding through an initial public offering or sale to another investor, he told reporters during a conference call.

VTB and its partners will get a 55 percent stake in T2 RTK Holding, with Rostelecom having 45 percent. Soloviev said that Rostelecom could raise its stake in the future - through a possible public share offering or if one of the partners sells.

Rostelecom approved the spin-off of its mobile business, including several operators and voice and data licenses, last year, but will have to buy out shareholders that did not support the move.

Soloviev said VTB could help Rostelecom to finance the buyout, but denied an earlier report in the Kommersant newspaper that it might purchase shares in Rostelecom.

Analysts have said it remains to be seen whether an enlarged No.4 player will be able to defend its position and grow in the short term. Tele2 sold out of Russia because it did not see strong enough growth prospects after failing to secure 3G and 4G data licenses.

France deployed 1,600 troops to its former colony in December to stem violence between Christian militias and largely Muslim Seleka rebels who ousted President Francois Bozize last March.

Asked during a radio interview whether France's U.N. mandate, granted on December 5, would have to be renewed, Le Drian said: "Probably."

He said that the French mission had helped ease tensions in Central African Republic, a landlocked nation of 4.5 million people, and that the security was improving day by day.

"The situation in Bangui has more or less stabilized," Le Drian told RTL radio. "In the rest of the country it is much more complicated."

France had hoped to quickly hand sole responsibility for security to the African Union peacekeeping force MISCA, which has deployed over 5,300 troops to Central African Republic, including soldiers from Rwanda, Burundi, Chad and Cameroon.

INVESTIGATION

Close to one million people, or a quarter of the population, have been displaced by clashes that began when Seleka rebels embarked on a looting and killing spree after seizing power.

Christian self-defense groups known as "anti-balaka" (anti-machete) took up arms against them. The United Nations estimates that more than 2,000 people have been killed in the violence.

In a sign of tensions running high in the capital, government soldiers on Wednesday lynched a man they suspected of having been a rebel.

The lynching took place minutes after interim President Catherine Samba-Panza called for reconciliation in an address to troops, and was condemned by France and the United Nations. Both called for an investigation and appropriate sanctions.

"The incidents yesterday are unacceptable. They must be investigated and punished," General Babacar Gaye, U.N. envoy in the country, told a news conference on Thursday.

The remarks came from Sigrid Kaag, head of the joint mission of the United Nations and the Organization for the Prohibition of Chemical Weapons (OPCW) that is overseeing the destruction of Syria's chemical arsenal.

Some mutual funds are already down 10 percent so far this year, thanks to declining stocks and currencies. And that drop has intensified selling pressure as investors rush to pull more money out.

"It has been a disappointing beginning of the year," said Will Landers, a BlackRock equity portfolio manager with close to $4 billion in assets under management. The BlackRock Latin America Fund is off 10 percent this year.

Generally, hedge funds appear to be weathering the sell-off better. Many managers reduced their exposure to emerging markets late last year because of shaky economic prospects, and the current volatility creates more opportunities for those who use short strategies.

Emerging markets had been the darlings of the financial world between 2009 and early 2013, driven by a belief that countries such as China and Brazil would lead global growth in the next few years, while developed world economies would remain nearly stagnant.

But emerging markets investors have turned nervous for many reasons, from the U.S. Federal Reserve's pullback in its bond buying program to upcoming elections in India, Brazil, Turkey, Indonesia and elsewhere. The street battles between protesters and the authorities in Ukraine, turmoil over elections in Thailand, and bomb blasts in Egypt are not helping either.

So jittery are investors that a shock 425-basis-point hike in interest rates by Turkey's central bank last week did not even buy the currency a 24-hour reprieve before selling started again.

Illustrative of this is the iShares MSCI Emerging Markets fund, which is down 9.7 percent in 2014 through Wednesday. The ETF - the second-most actively traded in the United States - ended last year down 5.8 percent and rose 17 percent in 2012.

Fund investors worldwide pulled $6.4 billion from emerging market stock funds in the week ended January 29, their biggest outflows since August 2011, according to data from a Bank of America Merrill Lynch Global Research report.

And investors and analysts say that the debt markets can be just as treacherous.

The world's dominant search engine has been the focus of a Commission investigation since November 2010, when more than a dozen complainants across Europe accused the company of promoting its own services at their expense.

Google has now made three attempts to resolve the case, with the latest moves looking like they will be enough to settle it, although there will still be a chance for Google's competitors to provide further input.

"I believe that the new proposal obtained from Google after long and difficult talks can now address the Commission's concerns," European Competition Commissioner Joaquin Almunia said in a statement.

The Commission said it would make a final decision after obtaining feedback from Google's rivals. Google's offer only covers Europe and would be valid for five years.

In a statement, Google said it hoped to draw a line under the case soon.

"We will be making significant changes to the way Google operates in Europe," said General Counsel Kent Walker. "We have been working with the European Commission to address issues they raised and look forward to resolving this matter."

Reuters reported on January 29 that the EU's competition authority and Google were close to a deal to resolve the investigation.

Google's success in escaping possibly heavier sanctions mirrors a similar outcome in the United States last year, where Google received only a mild reprimand from the Federal Trade Commission.

Almunia, who has been in charge of antitrust issues at the European Commission since 2009, has developed a track record of resolving cases via settlements rather than fines.

Google's ability to resolve competition issues in two major regions without a fine stands in sharp contrast to rival Microsoft, whose prickly relations with EU regulators landed it total fines of more than 2.2 billion euros over the past decade.

Under its latest proposals, Google, which has a 75 percent share of the European search market according to consultancy comScore, will let three rivals display their logos and web links in a prominent box, and content providers will be able to decide what material Google can use for its own services.

Google will also scrap restrictions that prevent advertisers from moving their campaigns to rival platforms such as Yahoo!'s search tool and Microsoft's Bing.

The pressure to boost security spending comes at a time when merchants are already spending millions to fend off online retailer Amazon.com and facing an October 2015 deadline set by payment networks Visa Inc and MasterCard Inc to accept new payment cards that store information on computer chips rather than on traditional magnetic stripes.

Target, the No. 3 U.S. retailer, said this week it hoped to finish upgrading its payment card network to the more secure "chip and PIN" standard by early 2015, some six months ahead of its previous plan.

The system, already widely used in Europe and Asia, can accommodate cards carrying tiny microprocessors, which makes it harder for cyber crooks to use stolen data.

U.S. retailers have been so focused on cutting costs and expanding their online presence in the past decade that they have not spent enough of their technology budgets on protecting customer data, security experts and IT service providers said.

While retail spending on overall technology was expected to rise 4 percent annually between 2012 and 2017, U.S. stores spend only roughly 2 percent of their tech budgets on security, with the bulk going to improving their e-commerce, technology advisory firm IDC Retail Insights said.

Unlike their peers in other industries, most retailers still focus on just meeting the basic standards set by the payment card industry rather than substantially beefing up safeguards against increasingly sophisticated attacks, security experts said.

"Retailers have to assume that they are constantly being targeted and actually constantly being penetrated," said Eddie Schwartz, a vice president at Verizon Enterprise Solutions, who urged retailers to take a more proactive approach.

Pressure from Congress, consumer groups and the banking industry following recent theft of customer data at Target, Neiman Marcus and others may be the turning point to get the retail industry to spend more on security, experts said.

For example, Dinesh Bajaj, the vice president of retail and logistics practice in Americas for Infosys Ltd, expects retailers to spend more in coming months on encrypting credit card data while storing it in multiple systems.

Whether browsing the Web on Internet Explorer on a PC running Windows or working up a PowerPoint presentation with Microsoft Office before taking a break to game on the Xbox, there are many among us whose entire digital experience have been filtered through products Gates helped create.

On Tuesday, Gates took what may be his final step away from leadership of Microsoft. With the announcement that Satya Nadella, a 22-year veteran of the company, will take over as CEO, the company also said Gates is stepping down as chairman of its board of directors.

Gates co-founded the company with Paul Allen in 1975 but stepped down as CEO in 2000. He then spent eight years as Microsoft's chairman before stepping away from full-time work there in 2008 to focus on his charitable work through the Bill & Melinda Gates Foundation.

Rather than exiting the stage at the world's largest computer software company, Gates may actually be getting more active. He'll take on a new role as an adviser to Nadella, putting him back on Microsoft's Redmond, Washington, campus more often. It will also put him nearer to the heart of innovation the company will need to keep up with rivals like Apple and Google at the top of the consumer-tech industry.

If he succeeds in helping Microsoft get back its swagger, particularly in a fast-growing mobile world dominated by Apple and Google and in the increasingly important field of cloud computing, it would be a final contribution to a career that has virtually defined an industry.

"Bill Gates is one of the pioneering giants of the information age," said Merv Adrian, a software and hardware analyst at Gartner Research. "Driven by the belief in a computer in every home, on every desktop, he helped to build one of the largest firms in the world to achieve that goal -- and arguably succeeded."

For starters, Microsoft was the world's first real software company. Although there are hours of bare-knuckle geek brawling to be done over whether Gates and Microsoft or rival Steve Jobs and Apple were the true innovators on early computer interfaces, there's no question as to who succeeded in making software for the masses.

The U.N. watchdog for children's rights said the Holy See should also hand over its archives on sexual abuse of tens of thousands of children so that culprits, as well as "those who concealed their crimes", could be held accountable.

The watchdog's exceptionally blunt paper - the most far-reaching critique of the Church hierarchy by the world body - followed its public grilling of Vatican officials last month.

"The Committee is gravely concerned that the Holy See has not acknowledged the extent of the crimes committed, has not taken the necessary measures to address cases of child sexual abuse and to protect children, and has adopted policies and practices which have led to the continuation of the abuse by and the impunity of the perpetrators," the report said.

The Vatican was expected to issue a statement on the report later on Wednesday.

The U.N. committee on the Rights of the Child said the Catholic Church had not yet taken measures to prevent a repeat of cases such as Ireland's Magdalene laundries scandal, where girls were arbitrarily placed in conditions of forced labor.

It called for an internal investigation of the laundries and similar institutions so that those who were responsible could be prosecuted and that "full compensation be paid to the victims and their families".

A commission created by Pope Francis in December should investigate all cases of child sexual abuse "as well as the conduct of the Catholic hierarchy in dealing with them," the report said.

Abusers had been moved from parish to parish or other countries "in an attempt to cover-up such crimes," it added.

"Due to a code of silence imposed on all members of the clergy under penalty of excommunication, cases of child sexual abuse have hardly ever been reported to the law enforcement authorities in the countries where such crimes occurred," the U.N. body said.

At a public session last month, the committee pushed Vatican delegates to reveal the scope of the decades-long sexual abuse of minors by Roman Catholic priests that Pope Francis called "the shame of the Church".