Google AdSense is known for its uncanny relevance in serving context sensitive ads. Its competitors like Yahoo Publisher Network and Kontera aren't being able to make significant inroads to AdSense / AdWords customer based primarily due to relevance, perceived or otherwise. However recently I am starting to see completely irrelevant ads as far as contextuality. The problem is deeper than simple not having relevant ads or even CPC ads. I suspect the problem is in the algorithm.

I have experiemented with all the available WordPress plugins for comment spam protection including but not limited to Bad Behaviour, Spam Karma 2, Akismet and built-in WordPress features like blacklists and moderation queue. We have to deal with tens of thousands of spam everyday. The key problem with all of these plugins is high rate of false positives along with some false negatives too. In plugins where false negatives are low (like Spam Karma or Bad Behaviour), false positives are unacceptably high. False positive is a condition where a legitimate comment is identified as spam. It is a much bigger problem than false negatives (inability to mark a spam comment as spam). While false negatives are a problem in terms of annoyance, false positives are much bigger problem. It causes you to potentially lose valuable comments, feedback and even business opportunity; I speak from first-hand experience.