Suggestion: Hide threads from the main page

I'm really fed up of seeing the thread list filled with inane drivel (a current example being 'Do you have white hair?'), and having to scroll through before something even vaguely interesting turns up. An ignore button, to hide this torrent of crap, would be much appreciated.

(I forgot to mention this in my first post, but closing off user-created groups, so they only appear on the main thread list if you're already a member of the group it was posted to, would be great too)