Also for you all hanging out on tumblr who want to know about spoilers -- OR to help others know where you stand on 'em:
Get thee to the Sherlock Spoiler Warning Generator!
My golly. I can tell that Sherlock fandom is strong in the tumblr, for this is pretty damned brilliant. I hope this exists for other fandoms too!
Thanks to the marvelous Final Problem for this info. Her spoiler policy for Sherlock series 3 is here.
I highly recommend her Reichenbach theory index.
If you want the fast version, try The Writing on the Wall instead. I have TWotW linked in my sidebar; and I think anyone who wants desperately to know what the possible theories, clues, happenings, and everything else Reichenbach should check it out... and then get sucked into the theories. 8) Get popcorn and expect to stay for hours.