Many APIs eventually find their way to the ProgrammableWeb deadpool. They end up there for various reasons: no business model, replaced by a newer service or ceased being useful. The most popular of these dead APIs are predominantly from two big tech firms: Google and Yahoo. Search and mapping make up the bulk of the functionality behind these 12 popular--but no longer available--APIs.
1. The Google Search API was Google's first. It was released in 2002, but stopped registering new developers in 2006. The search giant finally pulled the plug on this SOAP service in 2009.
5. The 411Sync API remins the second-most popular SMS API (behind Twilio) based on mashups. This is quite a feat considering it's been gone since 2008.
6. The Yahoo Geocoding API was once the go-to resource for converting addresses to geo points. Google's own geocoder requires every call result in adding the point to a Google Map. There was not the same restriction on Yahoo's geocoder. A similar paid service is now available as part of the BOSS API.
8. Oh, Digg. The downfall of the once mighty link community does not need to be rewritten here. As the company figures out what's next, perhaps we'll see an updated Digg API. For now, we consider it deadpooled.
9. The Technorati API sits alongside Digg as a former major player. Developers once used this XML-based service to get metadata on blogs from the company that was the de-facto blogger scoreboard.
10. The Yahoo Image Search API, like the main Yahoo Search API, is now available for a fee in the BOSS API suite of services.
Just outside the top 10 are two Google geo services, the Google Maps for Flash API and the Google Maps Data API. Neither have been replaces as Google focused its efforts on the wildly popular Google Maps API.
Perhaps there is a point to be made about relative popularity. Though these services are the most popular of those no longer available, only one cracks the top ten of ProgrammableWeb's most popular APIs overall.