Duotrope does something similar,of course, although that's just gone behind a $50/year paywall. There are other systems too. But I was very interested to learn about the Submitomancy initiative. This is currently trying to crowd-source funding in order to get off the ground.
Submitomancy is a tracking and social networking project aimed at writers and publishers. We will work closely with active markets; however our primary focus is to offer submission tracking system for writers of short fiction and poetry. Our basic service will be offered free to users with a simple sign up. Premium users will gain the advantage of the full library features, power searches and social interactions.
The premium level is planned to be $20/year, which sounds about right to me. There's a great interview with Sylvia Wrigley, the driving force behind the scheme, over on Alex Shvartsman's blog. I've been in contact with Sylvia to see if I could help with the development in any way, but the main issue right now is to spread the word and see if there is enough interest in such a system.
As with all these crowdfunding schemes, any money pledged is returned to you if the target amount isn't reached. At the time of writing, the initiative has £767 pledged with a target of £5,500 by January 29th.
I think there's huge scope for creating an invaluable system here. If it does take off, I might even stop using Writer's Database...