I don't know. In regards to Modifications, the attachments are really the only thing that need to be protected, and they are.

So if people are mirroring content, the viewers are going to eventually end up here if they want to download the modification.

It depends how much value you place on the actual posts as your content. Personally, I'd only let them index the modification titles :)

It seems to be a trend of late, I think a lot of these sites are MFA. I've stumbled accross several when trying to find vBulletin stuff - it's a pretty good tactic, take all this site's content - make your SEO superior to vB.org (not difficult) - profit from ad clickers.

I think I can partially see how they could benefit from SEO by allowing spiders to see more content but how do these fly by night copy sites get more superior SEO?