IIRC, there are exceptions in trademark law carved out for peoples' names. That is, someone whose last name is Google could not be prevented from using their name as the name of their company. There are likely some nuances to this, such as that the company couldn't bear the exact same legal name "Google, Inc." or choose the name with intent to cause confusion. Two names that existed in separate industries should be considered safe. This case of naming rights on a privately owned service further complicates the spirit of the law, insomuch as a private entity has control of most of the name and can rightfully choose who uses its service.
ICANN at least honors this sentiment for domains. See the case of Uzi Nissan is Nissan Motors v. Nissan Computer, who registered Nissan.com before Nissan Motors. Similarly in nature, Microsoft v. MikeRoweSoft existed, but was settled out of court.
Personally, I'd like to see Google and other services that offer naming of pages to follow similar guidelines: no one can be prevented from claiming their name.