Pfff. 13 users are much more than my pet project (http://www.DNSDigger.com) has. It is a couple of years old but i recently started with paid accounts and API-access.
A few thoughts:
-You should make the explanation of what your site offers a little bit more clear. It took me a few minutes to figure it out.
-What is the Google Analytics/Adsense lookup Database part? I can lookup sites that use a specific google analytics or adsense id?