Two things that have been mentioned by the creators (spoilers, don't scroll down if you haven't seen the finale):
-The show probably won't air again until early 2013 (“@Sherlockology: @Steven_Moffat was misquoted in The Guardian, no new #Sherlock until 2013 at the earliest” )
-That most of the deductions about how Sherlock survived were missing one vital clue, something that was completely out of character for Sherlock.
(“We’ve all worked out exactly how Sherlock Holmes survived at the end of the series finale, right? WRONG.
At our exclusive Radio Times covers party last night, co-creator Steven Moffat said there’s something in Sunday night’s episode, The Reichenbach Fall, which everyone has overlooked.
Moffat admitted he had been following the fevered speculation about how Sherlock, played by Benedict Cumberbatch, could appear alive and well in the last scene of the episode, despite having apparently fallen to his death and, indeed, been buried. But according to Moffat, all the fans’ talk of switched corpses and mystery cyclists has been lacking a crucial detail.
“I’ve been online and looked at all the theories,” Moffat told us, “and there’s one clue that everyone’s missed. It’s something that Sherlock did that was very out of character, but which nobody has picked up on.”
What does he mean? Of course we tried to convince him - and fellow Sherlock creator Mark Gatiss, who also attended the party - to elaborate, but Moffat merely smiled and said that was all we were getting!
Over to you…”
-Steven Moffat for Radio Times)