About spiders/bots
This plugin works by setting a cookie to track the number of visits from a particular user. As bots do not tend to accept cookies, they should not be blocked. To further insure there is no spider accessibility issues, there script identifies major bots (google, yahoo, msn, aol) and explicitly lets them through -- you can easily add to this list by editing the plugin code should you so desire, however, unless a bot starts taking cookies this should not be necessary.