Twitter's vice president of product Michael Sippey has announced he's leaving his current position in favor of a smaller advisory role with the company. "Over the past few weeks I’ve talked with Dick and Ali about what I want next in my career, and what Twitter needs at this stage of its life," Sippey wrote in an email to Twitter's staff — also posted on his personal website. "And I’ve decided that it’s time for me to move on." Sippey doesn't reveal any specifics on those conversations with Dick Costolo and COO Ali Rowghani; instead, his goodbye letter hints that he'd prefer to work for a smaller, more nimble company where he'd have greater control. "I’ve spent most of my career working at startups, helping them scale and having a direct hand on the product," he said.

In his advisory position, Sippey says he'll provide input on overall product strategy and Twitter's 2014 roadmap. He also plans to help Rowghani find someone to fill his vacant VP slot. "After that, I’m excited to go figure out what’s next." In December (before any news of his departure), Sippey shared his team's desire for quick and constant innovation in an interview with The Verge. "In terms of where we want it go, we’re constantly working on that — constantly," he said. "You have to continually be revisiting that, because the world changes, consumer behavior changes, the competitive landscape changes. And you want to be able to react to that." Sippey's departure suggests that, for all of Twitter's experiments and beta testing, those reactions still weren't coming quick enough.