I do not use the wpmu section of it because it is hard to get any to stick. (last use 250 stuck of 3k) the pligg stories are ok for links, the hooks for content and pictures are nice. The links stick also as backlinks. pligg comments work wonders for indexing (10 normally do it within 12 hours) success on pligg has diminished, This could be improved by using a catchall domain (i dont) and may have to set that up. so At one time I would recommend buying, but not really at this time, and suggest using a crack. Pligg stories do seem to help with ranking on alltheweb/altavista, somewhat on yahoo search engines.