I noticed on my site a surge in traffic with a live search referrer, where the initial searches had a very generic term, and subsequent searches were closer and closer to the topic of my site. After testing extensively, I determined it was some type of bot, but that was as far as I could get.

I would suggest checking the IP addresses of the incoming requests, look for traffic coming from the same class C (1.2.3.x) addresses. Once you find the class C block they are using, you can block them through .htaccess. Of course, if this is an MSN bot, it is unknown what effect blocking this traffic might cause on your rankings in MSN.

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The best way to learn anything, is to question everything.