Speculation: Who is Gossip Girl?

   Georgina's recent attempt to be gossip girl only served as a way to turn our attention back to the key-question of the series... Who is Gossip Girl?

 

Georgina in last night's episode realised that being Gossip Girl was way too tiring and didn't really satisfy her... So the real Gossip Girl at the end of the episode's suggests that when she will come back from her long vacation, everything will seem like a different world.
    Over the years, Gossip Girl has played a major role in the development of the storylines of the main characters so much that it makes her a main character as well. Her comments sometimes mean, sometimes prophetic, most of the time entertaining and indicative, speak volumes about her/his personality. The way she/he is writing also shows a person who knows her/his subjects a little too well. Even from the first episode, she/he was aware of Nate's crush for Serena which couldn't be common knowledge in high-school and even though Chuck was sending her/him blasts very frequently, I don't see him telling her/him either. This could probably give us the first clue.
1. Gossip Girl knows them personally and is probably someone from their close environment.
2. As Serena, Blair, Nate and Chuck assumed in the season 2 finale, she is probably from their class or at least at their own age, since she started the site when they were too young for anyone older to care about.


     Once I found out that Nate had never sent a blast to Gossip Girl, I thought that he could be a good candidate. It would be very socking if it was Nate all along. But seeing him sending and receiving messages from Gossip Girl and taking into account the things Gossip Girl has written for him over the years, I excluded him since it would be crazy for him to do so.
     Another suspect I've been thinking of lately is Vanessa. Once she came back from her year long absence, she commented on Serena having experiences with boarding school proffessors... And we find out two years later that she was suspected of doing that. She had access to the school through Dan and has always been the curious observer who makes documentaries about the Upper East Side. She has never sent a blast through Gossip Girl, not at least until the ending of season 2 as she wasn't invited in the little party Gossip Girl has organised back then to show Serena all her senders. If she were Gossip Girl why would she need to send herself an email? The way Gossip Girl shut down after the accident, reminds me of the way Vanessa escaped the city after what happened to Serena out of guilt. She knows Georgina and has befriended her in the past so I could she her giving her Gossip Girl maybe after she's been blackmailed by Georgina. Actually, the more I think about it, the more convinced I get that this is an actual possibility.
     Then, there are those three little girls that seem to read Gossip Girl fanatically and having very strong opinions. I doubt it because of their age but it wouldn't suprise me either if it was them all along.
Or there is the possibility that Kristen Bell herself will play the part. I mean she's been narrating for years as Gossip Girl so it wouldn't be that weird. Actually it would make more sense than all those speculations. And if this is the case I would really be interested in finding out more about her. What motivated her in the first place?  Is she related in anyway to our main characters? Where does she come from? Is she an Upper East Sider or a Brooklyn resident or something entirely different? Is she Serena's sister (as these days anyone with blond hair should be suspected)?
So, what do you think? Do we already know Gossip Girl or is she a total stranger?