I would like to block someone's posts/threads, I find them offensive at some points and don't want to read them.
Is this possible?

Yes. Go to your UserCP and scroll down the menu on the left, you'll find a link for your buddy and ignore lists. You can add and remove people from there. You can block anyone except moderators

Thanks for your help! Can you tell me why I have a "referral" on my profile?
Thanks!

When someone registers for an account, there is a field that asks for username of who referred you here, if someone referred them. So someone gave your username. Thanks!!