martinibuster - 2:32 pm on Sep 18, 2012 (gmt 0)
If there is no editorial decision on the wiki pages, then it does violate Google's guidelines. For example, there are many wiki pages hosted online by public and scholastic entities that aren't really curated because nobody's really in charge of it. There is no wiki community behind it, just some professor, scientist, or regular worker who put a work ticket in to their IT to put a wiki up so they could post something mundane to the web. In that case yes, it's a violation of Google's guidelines. I have seen these pages, pretty nasty situation.
Google catches on to duplicate content, so it may not even be helping them that much.
The duplicate content thing relates more to the ranking ability of the duplicate page, and it's debatable whether there is an effect on PageRank flow.