It’s called Vote to Play, and it’s exclusive to PlayStation Plus members. The concept is pretty straight forward: Sony will put up three games that members can then vote on; the game with the most votes becomes the free game in the Instant Game Collection the following month.
There’s potential for this to be really great AND really frustrating as you watch in horror as the game you want slowly falls into third place. I mean, people just have terrible taste in games, don’t they? How are you going to convince the sheep that YOUR game of choice is, like, the only choice? The good news is that the two titles that fail to drum up enough votes will be given a drop in price that same month. So while you might miss out on bagging Super Tri-force XD Ultra Omega Tournament Edition for free, you’ll get to buy it for less. Note that that discount will also be exclusive to PlayStation Plus members; non-members can get in the sea.
Note 2: that header image was picked up and leaked by NeoGAF; Sony has yet to unveil anything further than the blog post announcement for this promotion. Another aspect worth pointing out is that Sony has only announced this for PlayStation 4 titles; there’s no word on whether Vote to Play will feature PlayStation 3 or PlayStation Vita options.
Source: PlayStation Blog