incrediBILL - 5:30 am on Dec 6, 2007 (gmt 0)

Now you know why I use a combination of methods.

Cached reverse DNS lookups for a quick test for bot validity and if that fails I check to see if it at least belongs to a range owned by the company associated with the bot and do this for Google, Yahoo, Microsoft, Ask, Gigablast, etc.

[edited by: incrediBILL at 5:30 am (utc) on Dec. 6, 2007]