I see several YC startups in Google's collision path and for some time I have wondered if the advice of not competing with Google in things they are good at is valid.
http://www.techcrunch.com/2006/09/02/an-interview-with-vc-pa...
My opinion is that it never was valid: most startups at the list bellow were doing things Googlers are good at and they got adcquired, and those startups' ideas weren't so wild (according with the second advice in that interview).