It's the user profiles that I find you have to watch out for (since users can modify them anytime). Also I have had clients who have had their site hacked and the hack just changes content for the google bot. You may want to check those urls when mimicking the google bot on your site.
Frankly your example is why I think Google is broken now. No real link building on my part either and I have a lot of nice links but I also have a ton of spammy links built by bots from who knows who.