ThinkProgress will soon become the latest publisher to leave Medium.

The progressive news organization, which is housed by the left-leaning Center for American Progress, will no longer publish on Medium beginning Aug. 1, founder Judd Legum said. They'll be moving to WordPress, which the site used before it migrated to Medium last year.

In doing so, ThinkProgress joins an exodus away from Medium that began early this year after the company announced that it was laying off 50 staffers in a pivot away from advertising-supported publishing. Several of Medium's marquee publishers, including Pacific Standard, The Ringer and Film School Rejects have already left, citing chagrin with the company's new direction.

At issue for most publishers was the decision made by Medium to discontinue its "promoted stories" native advertising program. That program was a lynchpin for agreements between Medium and publishers that guaranteed them revenue based on the amount of readership they were able to draw. Without promoted stories — and an ad sales staff on Medium's side — there was no basis to keep the money flowing.

But the lack of advertising wasn't the reason ThinkProgress decided to leave, Legum said. It was the prospect of remaining on a platform that wouldn't continue to be developed with publishing organizations in mind.

"I'm certainly not eager to have a bunch of ads on the site — and we're not going to," Legum said. "I'd love to have none. And if it were possible, I'd be interested in figuring out a model where we don't have to have any. But if it's connected to a platform that's not going to be developed with publishers in mind, it doesn't really make sense to think through that as a platform. That sealed it for me."

ThinkProgress, which draws 8 to 10 million unique pageviews per month, is likely among the biggest publishers to announce its departure from Medium to date. But Legum said it will continue to receive revenue from Medium until the beginning of August, when its contract expires.

But the revenue loss won't mean ThinkProgress is planning on cutting staff. On the contrary, Legum said. The site, which currently has between 35 and 40 employees, will add about 10 staffers this year as part of a push to beef up critical scrutiny of President Trump. The site just finished a $500,000 crowdfunding campaign calling on readers to "Support the Trump Investigative Fund," and it will use those proceeds to grow the staff by 30 percent.

That crowdfunding campaign has combined with increased interest among deep-pocketed donors to support journalism in the wake of President Trump's election to give ThinkProgress extra revenue, Legum said. Those hires will be made as quickly as possible, but they might take some time.

"I'd like to do it yesterday, to be honest with you," Legum said.