Joe Ricketts could not stop the trend of media outlets unionizing. In fact, he may have helped it.

Seven months after the TD Ameritrade billionaire shut down DNAinfo.com rather than accept his employees' decision to unionize, the Writers Guild of America East says it is bringing more digital media outlets than ever into its fold.

Fast Company has become the 14th outlet (15th if DNAinfo is counted) on the Writers Guild's media roster, adding to a streak that has seen Vox Media, the Dodo, Talking Points Memo and the Onion join the ranks since January.

A "clear majority" of Fast Company's 40 editorial, social and photo staffers signed union cards to make the Writers Guild their collective-bargaining representative, the union announced Wednesday.

Organizers at the business publication, which operates a website in addition to putting out a magazine eight times a year, stressed that they were not complaining about their working conditions.

"Fast Company is a great place to work," said Morgan Clendaniel, a senior editor and organizing committee member. "Everyone feels pretty good about it. But things can go south fast anywhere, and it's always good to have a contract in writing."

Parent company Mansueto Ventures only learned of the unionizing effort Tuesday morning. In a brief phone call, Chief Executive Eric Schurenberg said he had been taken by surprise and could not comment on whether the company, owned by Morningstar Chairman Joe Mansueto, would recognize the union.

"It's way too early to respond," Schurenberg said.

The Writers Guild began its digital-media organizing three years ago with Gawker Media (which survives today, after a devastating lawsuit, as Gizmodo Media), and now represents close to 1,200 employees, according to Executive Director Lowell Peterson. The union found that job insecurity, uneven pay and the lack of clarity around company policies helped make it fertile terrain for organizing.

Ricketts' pulling the plug on DNAinfo and sister site Gothamist reinforced those concerns.

"We negotiated a really strong severance package for people there," Peterson said. "And they became evangelists. They helped us organize more shops."

If anything, he added, the experience with DNAinfo "inspired people. This is the reason you need to have a collective voice."