Twitter cofounder and Medium founder and CEO Ev Williams is making the press rounds these days. Last week he sat down with CNN, and the conversation landed on the topic of misinformation and fake news. In his estimation, the real problem is the system that’s driving it: ad platforms. “In my opinion, the most nefarious feedback loop,” he said, “is that it’s all driven by advertising.”

His point is that platforms like Google, Facebook, and Twitter care about users’ attention–they don’t care what kind of attention it is. “If you can generate attention you get paid,” said Williams. “If you yell fire in a theater, you still get paid.” This creates a system where advertisers bombarded the platforms with ways to make people notice, no matter what. “Attention gets rewarded and not quality of information,” Williams said.

This is a particularly poignant point for Twitter, which is seeing an influx of bots being used as political weapons. With investigators asking Facebook questions about Russia’s interference in campaigns, Twitter will likely be facing similar probes around its fake user and fake news problem. The company has said it’s seeking ways to fight the problem, among others related to violence, hate, and terror on the platform.

Williams’ opinions connect directly to his latest pitch for Medium. The site is now trying to rebrand as a subscription service for the best content on the web. Most importantly, it’s trying to figure out a revenue model for web publishing that doesn’t rely on ads. The idea is to create a system that rewards quality work instead of merely attention-seeking. “I think about it a little bit like Google’s search quality algorithm,” he told me during a recent interview. “It’s probably not going to be super transparent what [those factors] are.”

During our time together, Williams explained what Medium is now and what its plans are for the future. You can read the story here.