Hey jsankey, the advantage of Curbit is simplicity. All existing solutions require a fair amount of effort of the person wanting to get rid of something. Freecycle is solving the exact same issue, but I feel that the burden that comes from having to manage pickup / messaging / condition reports all from a very rough web UI deters a huge portion of the population. We shouldn't have to work to get rid of something for free :)

Compared to classifieds in general, it can be much simpler to use, because money isn't changing hands.