Google suffered a symbolic loss on Wednesday as its Senior Product Manager for Android said he would leave the company for Facebook effective Monday. He didn't explain his exact duties at the social network but said he would help "innovate at the intersect of mobile and social," suggesting his phone OS work will carry over. Neither of the involved companies has yet to comment or indicate who would take Tseng's place.

Most early expectations have Tseng developing the mobile components of Facebook, although this wouldn't necessarily limit him to writing for Android. The site already has a mobile app for Android but also writes for the BlackBerry and iPhone. It has also been working with Microsoft and Palm on linking Facebook through the entire Windows Phone 7 and webOS platforms.

The exit is ill-timed for his now former employer, as it comes exactly a week before Google' I/O conference. The search firm is expected to show off Android 2.2 and may also use the event to show any collaboration on a tablet for Verizon. It could also show the first results of its Google TV project, which would use a custom version of Android to bring Internet features to set-top boxes and directly to some TVs.