Possible Exploit/ Flaw

I am a moderator for a site that is hosted through forumotion.
Today, we had a spammer spam every board with certian content in his posts, which enabled him to redirect to others sites. It also makes it slightly more difficult for admins to delete the posts, as you have to turn off Meta Redirection in your browser to even be able to see the post.

So you guys know, the code he is using is:
<meta http-equiv="Refresh" content="0;url=http://lawl.insanehost.info">
So beware, your site may get mega-spammed through these.
Just though I'd warn you guys