They could block airbnb IP's address if airbnb directly posted the listing. But since it's the user who actually does the posting... However, craiglist could m

They could block airbnb IP's address if airbnb directly posted the listing. But since it's the user who actually does the posting... However, craiglist could make life hard for irbnb by changing their form field names. Then again airbnb could probably detect the changes. Probably the best way for craigslist to deter airbnb would be to have a single field at the start of the listing process. :)