I actually just released <a href="http://sit4.us" rel="nofollow">http://sit4.us</a> as a tool for coordinating your existing network of babysitters.  I kind of figure that having to deal with lost traffic is like having to deal with scaling, it's a problem I wouldn't mind having because it means that people are at least trying to find my site.  On the other hand, this is really just a little tool I built because I wanted to use something like it and I couldn't find any existing tools out there.  If I was really banking on it becoming a business than maybe I would have covered my bases a little better with the domain name.