There was a problem this morning using the UBB code to post links (that is, the square brackets plus URL=insertlinkhere), all of which showed up as a closing square bracket ]. Using the HTML standard of greater than/less than signs with a href="insertlinkhere" worked. I don't know if that's still the case.
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .