What is Stewart Butterfield up to?

AllThingsD’s Kara Swisher reported earlier today that Flickr Co-founder Stewart Butterfield is working on a stealth new company in the social-gaming space. Doesn’t sound like much of a surprise considering Butterfield’s priority at Vancouver-born Ludicorp was a social game titled Game Neverending until it got shelved in favor of Flickr.

Yesterday, several Flickr engineers posted news of their layoffs from the Yahoo photo-sharing unit on Twitter, which caused GigaOm’s Om Malik to notice that Flickr architect Cal Henderson (pictured here) was also no longer on its About page.

According to several sources I spoke to, Henderson was actually not laid off at Yahoo (YHOO), but is leaving to start a new company–in the social-gaming arena, I am told–with Flickr co-founder Stewart Butterfield.

A quick glimpse of Butterfield’s Flickr account indicates that he is indeed in Vancouver this Spring.

So, who knows what he’s up to?

Photo by KK+