A link is dead
How it works
[...] You can add/delete/modify the keywords in the administration-menu. There are webpages that list the user-agents of known spiders and webcrawlers (e.g.
http://www.useragentstring.com/pages/Crawlerlist/). The most common bots are already in the default list of the plugin.
To be replaced by: http://www.useragentstring.com/pages/useragentstring.php