In the latest twist, the boycott has drawn Ms. Coulter, a self-described progressive liberal, into a growing debate over whether targeting Ms. Trump is sexist.

And she said she worries that people will think she is profiting from the venture. Ms. Coulter was particularly upset when a knockoff “Grab Your Wallet” group sold clothing and other merchandise on Facebook. “We don’t even have a T-shirt, we don’t have stickers, nothing,” she said, adding that she does not accept compensation from companies, or donations.

“I don’t think either of us envisioned that some of the things that have happened would happen,” said Sue Atencio, who helped Ms. Coulter get the site started.

In many ways, Ms. Coulter has embraced her new position. She answers emails at all hours and scours Twitter for tips on companies to add, or remove, from the boycott list. Then there are the phone calls — lots and lots of phone calls — from angry Trump supporters or journalists or the companies that want to get off her list.

There is no doubt that it has changed her life. She doesn’t sleep or socialize as often as she used to. Most of her work on Grab Your Wallet is done after she eats dinner with her husband, taking up what free time she has.

“She went underground, basically,” said Amie Penwell, a fellow San Francisco resident who hasn’t seen much of her friend of seven years recently.

The negative attention has made Ms. Coulter careful about her privacy. She insisted on meeting at the work space for an interview, to avoid having a reporter at her home, out of fear that it could be targeted. She would not let her husband, whom she met online in 2010, be interviewed.