I think there's a reasonable argument for Craigslist's aversion to offering an API and it's all down to performance and operating costs. Craigslist manages to

I think there's a reasonable argument for Craigslist's aversion to offering an API and it's all down to performance and operating costs. Craigslist manages to offer what may be the last free webservice that hasn't been forced to sell the personal information of its users and/or turn into an ad-infested mess. It manages to make a modest profit by running incredibly lean in terms of manpower and server resources. The incredibly quick and clean interface is a huge appeal for users. The problem with building an API is that you have now exposed your efficiently minimized infrastructure to the insatiable demand of content scrapers. The resources demanded by a search on a site like Padmapper are greater than those demanded by the same search made on CL. While a smart API implementation isn't the equivalent to loading every relevant listing, some data must be pulled from every one of those listings in order to populate the Padmapper map and provide filters for its users. My point is that an API would not only increase the demand for resources which CL must pay for, it would break their minimized monetization strategy that keeps the site cleaner and more usable than any other rival. While they could charge for access to the API, the amount they would have to charge would likely break the business model of sites like Padmapper. Padmapper was also relatively clean and ad free but require them to pay any sort of fee for access to Craigslist's data and they'd have to ruin their user experience in order to stay afloat. Craigslist is minimal for more reasons than simplicity for the developers and users. It's minimal because that's the only way their business model works.