Gabor Cselle, former CEO and co-founder of X challenger Pebble, has joined OpenAI to work on a secret project.
According to LinkedIn, Cselle has been employed by OpenAI since October and announced the news in a post on X yesterday. “I'll share what I'm working on in due course,” he wrote. “I've already learned a lot.”
Cselle is a repeat founder who sold his first company, Y Combinator-based mobile email startup reMail, to Google. His second company, native advertising startup Namo Media, he sold to Twitter before Elon Musk acquired the social network and rebranded it as X.
Nearly a decade ago, Cselle worked at Twitter as a group product manager, focusing on the home timeline, user onboarding, and logout experience. Cselle left Twitter to join Google in 2016, where he served as a director at the tech giant's spinoff Area 120 incubator.
Cselle began working on Pebble, originally called T2, in 2022 with Michael Greer, Discord's former head of engineering. Pebble offers a microblogging service that focuses on safety and moderation, has grown to a small but passionate community, and has raised funding from angles such as Android co-founder Rich Miner.
Ultimately, though, Pebble struggled to sustain meaningful growth. The company shut down last October and resurfaced as a Mastodon instance in November.
In May, Cselle joined the accelerator South Park Commons, where he worked on various generative AI prototypes, including an homage to the viral HQ Trivia.
Csell's hiring announcement comes the same weekend that OpenAI rival Anthropic landed its own high-profile new hire, Embark founder Alex Rodrigues. Rodriguez, who led self-driving trucking company Embark through a SPAC merger in 2021 (and then a fire sale to Applied Intuition in 2023), announced Friday that he will join Anthropic as an AI safety researcher.