I remember using Lean Domain Search in the past and that it was in fact "lean" and pretty well made, super fast and easy to use.
As for Preceden, how did you come up with the idea, and where do customers come from? That there are enough users of a tool like this to support you sounds amazing -- and I hope I don't sound dismissive: envious would be a better word!
Testimonials are actually pretty inspiring, but one has to scroll to find them; maybe a link at the top of the page would help one see them faster?
It makes one wonder how many other functions are waiting to be "webified" like this.