Bethesda Softworks yanked Prey 2 off of its upcoming slate in summer 2012 when it became clear that the game would not be ready anytime soon, but a newly discovered countdown site hints at a reveal related to the game scheduled for March 1, 2013. The website, AlienNoire.com, doesn't explicitly mention Prey 2, though NeoGAF users (via Joystiq) captured an image of the (now-changed) source code, which bore keyword entries for the game title and its developer, Human Head Studios.
A WHOIS lookup reveals the domain owner's name to be "The Collective," with an address in Tahlequa, OK. That's also where Tommy, Prey's protagonist, is from, and where the capital of the Cherokee nation was originally founded. Tommy is also a Cherokee. Add to that the fact that the newly edited source code for the website still includes a telling hidden reference to the first game's protagonist, with a message that reads "Tommy needs your help."
Bear in mind, it is entirely possible that this is the work of a creative fan who wants to get people talking about the absent game again. We'll just have to wait and see, until either Bethesada offers some comment or, more likely, until March 1 arrives.