Obviously, like most fans (I imagine) I'm uber-intrigued about Clara, who she is, who the two previous iterations of her have been, what lies the heart of this "most impossible person who ever existed" (or whatever the exact line is). I have...a Theory. We'll come to that in minute.
I've got a Google Alert set up for news articles about Doctor Who. Sometimes it links me to boring news stories about "a doctor, who let all his patients die," or something of that ilk, but most of the time it's good stuff. One about a week ago linked to an interview with Steven Moffat about the new series. With specific reference to the first episode, The Bells of St John, he said something like, the clue is in the title. Whether that was about the episode itself, or the Clara mystery, I can't remember (and sadly I can't find the relevant interview or the Google Alert post...), so I'm kind of winging it here. However, I'd wondered about that title myself. The obvious thing it brings to mind is the old nursery rhyme - "oranges and lemons, say the bells of St. Clements."
Well...it's not in the most well known version of the rhyme. It is, however, in an earlier, longer version of it (reproduced over at Wikipedia). Specifically, "Pokers and tongs, say the bells of St. John's." I don't pretend to know what relevance, if any, that has either to next week's episode or to the ongoing tale of Soufflé Girl and Chin Boy, but I'll just throw it out there...
The other thing...the Theory. Well, it's nothing much. It actually has its origins in a weird dream I had a couple of weeks before The Snowmen, and nothing in it was actually contradicted by The Snowmen, and indeed it seemed to be a bit reinforced by it, so I'm still sticking with it until it gets Jossed. Or, pedantically, Moffatted. But it's roughly like this: There is no such person as Oswin, or Clara, or whatever. She exists as some kind of empty shell, into which a personality can be implanted. (In the dream, this was loaded from a CD-ROM. Hey ho, I'm all into the modern tech...) Reading what I've just written, I'm thinking it sounds incredibly like Dollhouse. Interesting. Anyhow...Clara's personality has been implanted into an empty shell body twice that we've seen - Oswin, who we met in Asylum of the Daleks, and the Clara we met in The Snowmen. With at least one more iteration to come (I wouldn't be surprised if we meet at least two Claras over the next few weeks...). Hence, although they're not actually the same person, they look the same and have similarities of thought processes (the obsession with soufflés, identical dialogue in places - "run, you clever boy...and remember...").
Why is this happening? Simple. It's a trap. A trap for the Doctor. Someone knows him well enough to know that he'll be intrigued by this mystery and want to solve it.
Who's set the trap? I don't know. It's probably someone the Doctor knows of old. Because of what happened in Asylum of the Daleks, I doubt it's the Daleks. I suspect it's something that'll come to a head in the final episode of the new season, and then play out in the anniversary special, so I'd probably rule out the Ice Warriors and the Cybermen, as we already know they're appearing. The Master would be the obvious villain to roll out for the 50th anniversary - perhaps too obvious, though? I don't know.
Anyway, that's my theory, and I'm sticking to it. Until canon proves me wrong, at which point I'll write it up as an AU fanfic, along with the one in which the ninth Doctor, played by Bill Nighy, befriends a journalist called Rose Tyler who's investigating strange behaviour of politicians who it turns out are being replaced by exact duplicates in the form of Autons... I was always rather fond of that one, but never got very far with it...