i don't think this protects you. If a large company thinks you are infringing on a TM they will come after you.
Consider the case of Mike Rowe, a canadian HS student who started the company Mike Rowe Soft (mikerowesoft.com), an amateur web design firm. Despite a completely different spelling and containing the guy's real name, Microsoft still came after him w/ a large C&D order.
He ended up settling I think for some software & other misc expenses covered after the press got ahold of the story of big M$ going after a poor little student. His case is well known because it is unique. For every Mike Rowe, there are probably 100 people who just get their website crushed and shut down, and lose their domain name after a big corp goes crying to ICANN.