This is old news, literally: Chen left his spot as chief technology officer last fall, though he remains employed at Google (GOOG), which bought his company for $1.65 billion in 2006. “Steve shifted his focus to help with some Google engineering projects. He’s still involved with YouTube and invested in its success,” says YouTube spokesman Ricardo Reyes via email.

Google hasn’t officially named a replacement chief technology officer for Chen, and people at the company say the job no longer exists. But the highest ranking engineer at the company is now Louis Perrochon, who has been at Google since 2003.

Chad Hurley, who co-founded YouTube with Chen and Jawed Karim in 2004, remains the company’s CEO. But it’s not unusual for founders to move on from their companies within a few years of selling them.

The fact that Chen’s move  has gone unreported until now should underscore that his departure didn’t represent a major org chart reshuffling. The technical challenges of the site have long been handled by a large engineering team, which makes sense considering that the challenges themselves are large. YouTube now uploads 20 hours of video per minute.

Chen was reportedly working on a technology incubator project last fall along with BitTorrent co-founder Ashwin Navin; no word on what Chen is actually doing at Google now.

Here are Chen and Hurley in a video they shot and uploaded on Oct. 9, 2006, the day they sold their company to Google.