Marking a Blog as Mature or Spam

What does that actually DO? I’m using the Sitewide Tags Pages plugin to create a site-wide search blog, which is working wonderfully, but I’ve run into a hitch. I also use Buddypress, and because people’s blog posts are being published not only on their site but also on the search blog, the item is showing up twice in the Buddypress activity stream.

I tried marking the seach blog as mature, hoping that would stop the stuff it does from being put through the BP activity stream, but that didn’t work b(still got double posts in the stream). I’ve got it set to “spam” now, but that doesn’t seem to be doing much either. I definitely want posts to be shown in the activity stream, but only ONCE!