You could feed in a whole bunch of data to determine if a user is a bot or not: * Did they request robots.txt? * User-agent * Logged in vs. guest a

You could feed in a whole bunch of data to determine if a user is a bot or not: * Did they request robots.txt? * User-agent * Logged in vs. guest account (if applicable) * Number of requests/time period * Patterns of requests The real value of this kind of analysis (to me) is to bucket the types of visitors: * bot * well-behaved (e.g. googlebot, etc.) * valuable * not-valuable * badly behaved * visitor The valuable vs. non-valuable traffic is interesting to me, I've seen sites where the bot traffic was 25-35% of the total, and that some of the bots, though well-behaved, didn't really bring any business.