NOTE: I do not know the original source of the following teasers.
EDIT: HERE'S THE SOURCE THANKS TO PTS: http://www.cultbox.co.uk/spoilers/teasers/2742-sherlock-the-reichenbach-fall-hints
A certain item of headwear makes a return.
Stealing the Crown Jewels? There’s an App for that…
We hope you’ve been paying attention. Something said in A Study in Pink becomes very important.
Keep an eye out, Sherlock fans, for more than one nod to the Basil Rathbone film The Woman in Green
The first rule of the Diogenes Club: You do not talk in the Diogenes Club. The second rule of the Diogenes Club: You do not talk in the Diogenes Club.
James Moriarty, aka, Mr. Sex.
It’s grim. It’s very Grimm.
The writing’s on the wall(s). Keep an eye on it.
Silence will fall.