UPDATE 9/18/10 – THIS METHOD NO LONGER WORKS. I am looking for another method and will post about it when I find it. I leave the post up as a curiousity and for the comments, which include a possible solution.
If you accidentally block someone on Twitter, don’t panic. You can undo it, and if it was an accident, you really should!
The easiest way to unblock an account is if you remember the username of the person in question. In that case, type in http://twitter.com/theusername while you’re signed in to Twitter. On the right side of the screen, below the number of tweets, you’ll see this (with the account of follower I blocked):
Click on “unblock” and voila! You’ve unblocked the person. Then, if you meant to follow the person instead of block, don’t forget to do that.
If you don’t remember the name of the person you’ve blocked (and can’t discover it via, say, an email saying they were following you), all is not lost!
Type http://twitter.com/blocks/blocking.xml into your browser. You’ll be asked for your Twitter username and password, then after you’ve entered them, you’ll see a webpage that’s mostly full of programming code. In there, however, is also the list of everyone you’ve blocked.
You will have to scroll through the page, but you’ll likely be able to find the wronged party once you see how the format of the page works. Then go back to the top of this post and go unblock them!