Twitter has plenty of critics, arguing the company is overvalued or expressing skepticism about its ability to attract more users. But the company has two big cheerleaders, who are standing behind Jack Dorsey, the co-founder and chairman, no matter what.

They are Mr. Dorsey’s parents.

Marcia Dorsey, his mother, who was  one of the earliest users of the social network, was posting tweets of encouragement throughout the day.

In her Twitter bio, Ms. Dorsey suggests that she may be the “grandmother of Twitter.” In that case, Timothy Dorsey would be Twitter’s grandfather.

The parents of Twitter’s chairman own a company in St. Louis called MA Tech Services, which sells mass spectrometers. Many of their Twitter postings involve scenes of daily life, mingled with updates about their son’s companies, Twitter and Square.

Thursday was all about Twitter.