As best I can tell, it's a matter of corporate philosophy. Craigslist is predicated on local, person-to-person interactions. It has long taken pains to curtail uses of the system which allow aggregation of multiple CL local sites (there is, for example, no convenient way to search all of California for listings), or to include CL listings in third-party services.

As a long-time user of Craigslist, and a recent fan of padmapper, I'm disappointed, to say the least.

I do suspect it's time for some disruption in CL's space.