appears to be gaining traction really quickly right now. If you aren’t familiar with it, it’s a image sharing site which provides theme based “image boards” which people can “pin” items to (think of the old cork bulletin boards people hang on walls and pin photos and pieces of paper to).
It seems unusual to see a new image-sharing type of social media site to be gaining so much ground, and so quickly.

According to Google Insights, searches for “Pinterest” have climbed so quickly this year that it’s now on par with searches for “Flickr” and “Picassa”. While searches for the brandname do not equate with traffic/visits to the site, they typically do correlate pretty closely.
For SEOs, I recommend that you enjoy the not-yet-NOFOLLOW status, because it’s certain to come to an end really soon. I might also predict that as it stands now, I think Pinterest might make better long term sense as a user-interface feature of some other social media service such as Facebook, Twitter, or Google Plus. It might make for a very good acquisition for one of those services.