I could, but I've already got you on Ignore so I didn't see your post.
Seriously, click on the "Flag" icon and one of the choices is Ignore User. Where is the Flag icon? Just to the right of the time the message was posted. So, the post shows your name, the time, and then the Flag icon. Sometimes the Flag icon disappears, but if you move the cursor just to the right of the time, it should show up.