Automattic CEO Matt Mullenweg just delivered a brutal assessment of his company's biggest acquisition. Speaking candidly at WordCamp Canada 2025, the WordPress co-founder called Tumblr his "biggest failure," revealing the social platform burns more cash than it generates despite hosting over 500 million blogs. The admission exposes the harsh reality behind one of tech's most ambitious content platform integrations.
The confession came during what was supposed to be a routine community session, but Mullenweg's blunt honesty about Tumblr's financial struggles sent shockwaves through the WordPress ecosystem. "I need to switch [Tumblr] over to WordPress, but it's a big lift. It's over 500 million blogs, actually, and, as a business, it's costing so much more to run than it generates in revenue," he told attendees.
The numbers paint a stark picture of acquisition gone wrong. Since Automattic bought Tumblr from Verizon in 2019, the microblogging platform has remained a financial drain, sustained only by profits from WordPress.com, WooCommerce, and other successful Automattic ventures. The company's ambitious plan to migrate Tumblr's entire infrastructure to WordPress - announced with fanfare last year - was quietly shelved in July when the true scale of the challenge became clear.
"It's probably my biggest failure or missed opportunity right now, but we're still working on it," Mullenweg admitted, his tone mixing frustration with determination. The technical hurdles are immense - moving half a billion blogs across different codebases while maintaining uptime for millions of daily users represents one of the largest platform migrations ever attempted.
Automattic has been scrambling to contain the damage. The company laid off 16% of its workforce in April, with Tumblr resources reallocated to more profitable divisions. But those cost-cutting measures haven't moved the needle on profitability, leaving the platform in limbo between its current expensive infrastructure and the promised WordPress integration.
Tumblr's struggles reflect broader challenges in the social media landscape. Unlike Meta's advertising juggernaut or Twitter's subscription pivot, Tumblr has struggled to monetize its passionate but niche user base. The platform's creative community resists traditional advertising, while subscription models haven't gained meaningful traction.
The stalled WordPress migration carries implications beyond just cost savings. Moving to WordPress infrastructure would have enabled Tumblr to join the fediverse, connecting it to Mastodon and other decentralized social networks - a potentially game-changing feature as users flee centralized platforms.
Mullenweg's candid assessment comes as Automattic faces pressure on multiple fronts. The company's ongoing legal battle with WP Engine over open source contributions has divided the WordPress community, while competitors like Shopify pressure WooCommerce's e-commerce dominance.
During his talk, Mullenweg revealed that his community-tracking site WordPressEngineTracker.com shows nearly 100,000 websites have switched hosts amid the WP Engine dispute, with 74,000 going offline entirely since September. "There's a site called WordPressEngineTracker.com which is currently tracking a number of sites that have left a certain host," he said, encouraging users to "vote with your wallet."
The CEO also touched on OpenAI and AI integration, calling companies like OpenAI "too big to fail" while discussing plans to tag AI-generated content in WordPress themes rather than banning it outright. "We're not putting the genie back in the bottle" with AI technology, he acknowledged.
Beyond Tumblr, Automattic continues expanding its product ecosystem. The company's universal messaging app Beeper will add bridges to KakaoTalk and dating app messaging services, while WordPress Playground allows users to run WordPress entirely in browsers.
Mullenweg's rare moment of public vulnerability reveals the hidden costs of ambitious acquisitions in today's social media landscape. While Automattic continues subsidizing Tumblr's operations, the platform's future hinges on finding sustainable monetization - or risking becoming a cautionary tale about the limits of cross-platform integration. For now, half a billion blogs hang in the balance as one of tech's most respected CEOs grapples with his self-proclaimed biggest mistake.
