[nikatwork]

A link loop as in a dynamically generated menu structure that creates an endless loop for the crawler, or accidentally makes large numbers of very similar pages with similar URLs, etc. (Yes this can happen legitimately and by accident on retail/commercial sites).

[jmpe]

... or one of those plugins that generates fake mails for email-harvesting bots?

[nikatwork]

I haven't used one of those myself, but yeah that does sound dangerous - however you could just tell the Googlebot to ignore the link in GA and it should be fine. I've seen people do similar things to create infinitely deep directories to screw with evil crawlers, since the Googlebot should obey your directives.

[maaarghk]

would using rel=canonical protect against this?