It's basically an Interactive Alternate-Universe online newspaper, and acts as if we're in the time slot that's the last four months of Deathly Hallows. It'll last until Deathly Hallows Part 2 comes out. Anyway, here's the part where Snape comes into this. Pretty much all of the characters that are still alive at this time (The Death Eaters, Hogwarts teachers, students, etc.) have their own official MiM facebook accounts, and you guessed it, Severus Snape has the most likes, with over 1,000.
Now, I have had multiple conversations with Severus Snape, and it feel so awesome to be talking to him. He, as well as the other MiM people, stay in character so well, it feels like you're actually talking to them... So I consider him to be the real Snape.
Here is one of the conversations I've had with Severus Snape: