I have a site with 43 blogs, and I installed the plugin on 3 or 4 of the sites. Some of these sites contain as much as 22,000 posts over 9 months. I tried to prune the sites to posts old as 3 months. Over would be cleared. I am guessing the plugin has a lot of pruning to do with 22,000 posts, but it drastically performs so many mysql checks, that the site can no longer connect to the database. Once I suspended the account, all my other sites came back and were accessible.