Quad stocks (.0001) as I call them,they are also usually stocks with the highest risks of reverse splits and you will loose 99% of your money when it does , been there done that a few times. Since every tick or 2 can mean 50%-100% gains, they are a favorite amongst flippers.
These can bring in some easy gains, if you have the patience to sit on the bid, and sell for a couple of ticks at the ask. I call this type of play , a liquidity flip trade, as you see 10's of million of shares being traded and only moving a tick or 2 , dont get greedy or you will hold a bag in most cases