This type of approach has been around for a few years. I recall a similar bent with the Comedy Central “I Poop on Your Site” starring Triumph the Insult Comic dog. However, this approach to effect advertising on a localized basis is interesting.
Since it’s client-side, will the ad servers be able to pick it up? Probably not, but if you know, please post a comment.
Also, I’d love to know the adoption rate of this–however small. Sounds more like an attempt as a “buzz generator” that anything else. However, more of a buzz with advertisers than with the consumer.