Pownce, the media-rich Twitter competitor once labeled by the New York Times as “the hottest startup in Silicon Valley”, is headed to the deadpool after being acquired by Six Apart. The service, which was co-founded by Digg’s Kevin Rose along with Leah Culver and Daniel Burka, will be closing its doors on December 15. Users will be able to export their accounts to other services, allowing them to retain their messages and media, but it looks like Pownce users will have to turn to Twitter for their micro-blogging needs (if they haven’t already). Culver and Mike Malone (Pownce’s two engineers) will be integrated into the Six Apart team.