The Three Patch Podcast has, of course, a spoilercast for s4 setlock.
So, you should avoid them if you don't want to be spoiled. If you DO want setlock, rush right on over to Spoilercast 28. There's also LOTS of tags there. :D
Per Three Patch, s4 filming runs over quite a while: "Shooting dates, late March/early April through August" -- whooo!!
For those who do NOT want to be spoiled, you can block tags.
Whichever is your preference -- setlock or no setlock -- do respect your fellow fans. We do not have to agree. But we should get along.
Here is my setlock master post. I shall have a master post of s4 setlock (eventually there will be a link too). Until then, there's always my setlock tag to help you find posts.
My setlock policy, and an explanation of what setlock is, was posted back in 2013... which is when I began s3 setlock posts.
I mask spoilers, so you have to click on them to know what they are. If Team Sherlock posted something, particularly on Twitter, I decide whether it's teasing or a true spoiler. I also tag spoilers.
For example, Sherlockology only posts official items from the BBC, Hartswood Films, Team Sherlock, the cast, the crew, etc. Others do the same... such as the Baker Street Babes.