What do you think about the idea of hiding posts of users, which are on you block list?For example:
You click on a topic and the user XYZ (who is on your blocklist), made a post there and instead of showing the post, it will display:
This post was hidden, because the user who created it, is on your block list (similar to "Inappropriate Post Content")
Maybe there could also be implemented a link that says
Show post anyway, for the case that you want to have a look at the post.
/e:
Update:
I thought about a functionality where you can decide if you want block PMs, posts or both. (within the block list)
Here an example on how it could look like (sorry for bad paint skills!):
This post was edited by blah2k6 on Aug 9 2011 08:23am