The problem with putting people on your ignore list...
 

...is that you still have to see the threads they make and you still have to see that they make posts (even though you can't read them).

I wish that when you put someone on ignore, everything they do just didn't appear. I don't want to have to read their thread titles, and I don't want to read "This Person Is On Your Ignore List"

As it is now, the ignore this user function is pretty useless.