WordPress co-founder and Automattic CEO Matt Mullenweg admitted that Tumblr remains his “biggest failure,” citing the stalled plan to migrate its 500 million blogs to WordPress infrastructure. Speaking at WordCamp Canada 2025, he said the platform’s high operating costs and lack of profitability forced Automattic to prioritize other projects. Still, Mullenweg hasn’t given up, calling the migration key to Tumblr’s long-term survival and open web integration.
