hairycoo - 11:41 am on Sep 28, 2011 (gmt 0)

This is very interesting as I have the same problem on several sites.

Not just synonyms and stemmed versions, but a few strongly co-occurring terms and "n-grams" of various lengths.

Tedster, can I ask what you mean by the above and how do you figure out which are these co-occuring terms? Is it based on competitor research?