To get your official Web 2.0 certification, visit the folks at Certifyr. It is definitely a pretty nifty gimmick. You visit their site, provide some information about your website, and in return they give you back your compliance rating and a little HTML do-dad to put on your website.
This site was created by Adbrite, the self-styled “Internet’s Ad Marketplace.” My guess is that they created Certifyr so that bloggers (like me) would talk about it – potentially driving traffic to their main site and increasing their brand value. Well guys, if that was your goal then kudos to you. I had my fun. Ironically, Adbrite is only 38% Web 2.0 Compliant.