Receiving a message in Google Webmaster Tools that reads "Googlebot found an extremely high number" is not uncommon for large sites. We covered it many times, including back in 2008 but the big question is how do you avoid it?
It is not a simple answer. Often there is not much one can do outside of trying to restructure their navigation and site architecture. But John Mueller from Google did post some advice in a Google Webmaster Help thread this morning. He suggested using the nofollow attribute on some links for this specific example. Let me quote JohnMu:
One way to prevent these from being discovered could be to use rel=nofollow on the links to those pages, assuming you haven't done so already. Also, in particular for the /goto/ URLs, you could also consider tracking those links separately (using JavaScript) instead of redirecting them through that page.
Do you consider this message in Google to be serious and take action to minimize the message or do you ignore it?
Forum discussion at Google Webmaster Help.