About spoilers for series 3, the Baker Street Babes remind us that not everyone wants to be spoiled. Honor that as best you can; if you are a spoilery sort, do put it up on top of your tumblr, blog, etc. Use tags!
There's a blocking app for tumblr too, if you happen to want some help in blocking posts there.
Into the Hive Mind -- a lovely in-depth article about the fandom that waited, full of great links and well worth your time to read. You might need to take breaks; it's 5k words and very detailed.
The spoiler zone for season 3 starts here: