At WordCamp Canada 2025, Automattic CEO Matt Mullenweg called Tumblr his “biggest failure,” noting the challenge of maintaining the platform’s half-billion blogs while it remains unprofitable. Though plans to migrate Tumblr to WordPress infrastructure are on hold, Mullenweg said he hasn’t given up.
Depending on how you measure “success. It may have not made a whole lot of money but people seem to have fun on there.