Publishing platform Medium announced today that it had laid off 50 people — about a third of it staff — amid growing concerns about its advertising-based model. The company said it would explore alternatives to pageview-based advertising in the hopes that it can develop a lucrative, sustainable alternative for writers publishers. “While we could continue on our current path — and there is a business case for doing so — we decided that we risk failing on our larger, original mission if we don’t make some proactive changes while we have the momentum and resources to do so,” CEO Ev Williams said in a blog post.