The Fall 2012 Update currently rolling out removes Twitter and Facebook from the Xbox dashboard, and Microsoft have confirmed the apps are officially being 'retired.' Speaking to IGN, Microsoft said it's "retiring the Facebook and Twitter apps," although the company didn't comment regards whether or not they may ever return. Microsoft is recommending Xbox users instead access Twitter and Facebook via Internet Explorer 9, which is included in the Fall Update.
It was three Fall Updates ago when Twitter and Facebook arrived on Xbox 360. Yes, nearly three years ago when everyone logged in on that first day to tweet or post a status update from their consoles, then immediately reverted to however they tweeted or updated their statuses before. Ah, memories.