This isn't a new forum feature, but it's sorta hard to find, and, um, I didn't even know about it until yesterday.

If there's somebody on the forum whose posts just drive you nuts, you can add their name to your personal "ignore list", and their posts will not be displayed to you.
To use this feature, go to your Profile > Modify Profile > Buddies/Ignore List > Edit Ignore List. Under "Add To Ignore List", type in the person's username (if you type the beginning of the name, you'll get a dropdown list of matching names, and you can select the correct one).
After this, any posts by that person will show only the message "You are ignoring this user," and a link, "Show me the post," which does what it sounds like.
If you change your mind, you can remove people from your ignore list on the same Profile page.