here are some posts about online communities that I find very good for one reason or another
(Not a full list, no particular order, mostly from the running list we keep at @capiche. screenshots in this thread are their quotes, not my notes)
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Two thoughts: The best startups are masters of asymmetric warfare -- they don't fight on the battlefield the incumbent selects. And, users often understand their problems well but are horrible at suggesting features to solve these problems.