Shortly before midnight on Thursday, the author Shea Serrano was at his home in San Antonio, lying comfortably on his sofa watching television. He could not shake a bad feeling about all the low-wage and hourly workers losing desperately needed tips and shifts because of the coronavirus outbreak.

He felt he needed to do something. So he tweeted.

What for many would be a futile act — venting into an endless stream of chatter, jokes and invective — meant, for Mr. Serrano, activating his dedicated following of 345,000 Twitter users. By Sunday night he had raised $10,000 — not for a traditional charity like the Red Cross but to send directly to people who posted screenshots of student-loan statements and past-due medical bills.

Mr. Serrano’s tweet (which contained an obscenity) asked “who has a bill coming up that they’re not sure they’re gonna be able to pay,” then requested a copy of the bill and a Venmo connection. It has been retweeted nearly 10,000 times.

“I knew as soon as they started closing stuff down, we were going to do something,” Mr. Serrano, who published a 2015 best seller, “The Rap Year Book,” said in an interview. “I’m acutely aware what it means if someone loses even one shift. If you’re making $7 an hour and you’re not going to get $56, that screws up a lot of stuff.”