Let me start with some URLs
These are some of the world's largest brands and their profile names are taken by some individuals. Needless to say, there wil be some legal hassle down the line when the corporate communications or marketing departments wake up to the smell of Pinterest and try to get these assigned to their "official" ones. And Pinterest may simply oblige them for obvious reasons.
The interesting thing is that Microsoft who is generally a slow adopter on social media has already reserved http://pinterest.com/microsoft/ although no activities are going on in there. The popular tech blog TechCrunch seems to have been taken by someone else ( http://pinterest.com/techcrunch/ ) while the other blog Mashable has taken the profile and also is very active in it…
And no one else has gotten to Google (http://pinterest.com/google/) as of the time of this writing (March 10, 2012)
Everyone of the SocialNetGate customer has already got their profile names. If you are serious about social media, EVEN IF YOU ARE A SMALL BUSINESS, you should reserve the Pinterest profile name without any further delay.