Craigslist makes use of both Google Maps and Yahoo Mapquest to present locations of individual properties through links on the CL site.

Note that these are free links, not paid-for API calls.

Who's free-riding whom?

Craiglist provides links to Google and MQ, which is the basis of how the Internet and WWW works. Craiglist supplies the actual address data.

It would be different if Craiglist embedded the maps from GM or MQ, but in such case CL would probably do so with permission from those companies (possibly even--gasp--paying for the right to embed maps).

The point I was making is that CL are increasing the utility of their service by using Google/Yahoo to provide specific maps of property locations. The distinction is that the relevant data curation (property locations) is done by CL, not the mapping providers.

I also noted that API usage would have been paid (or at least licensed), so in that sense, CL are (legitimately) freeloading on Google and Yahoo. While the argument could be made that CL are sending traffic to these sites, that same argument would apply to Padmapper.