When Chad Dickerson started working as the chief technology officer at Etsy, a website at which artisans sell handmade goods, he noticed something curious about the company's Internet traffic. One of the top sources of traffic was a website called Heartomatic, which makes it easy for Etsy fans to tout their favorite items and sellers. It was all the rage -- receiving some 35,000 hits a day -- and sellers praised it on Etsy's forums. "Beware: once you start checking it will be hard to stop," posted one user. But Etsy had nothing to do with Heartomatic. It was designed by Julian Lievano, an Etsy user who spent two months building it as a labor of love.
The rise of Heartomatic inspired Dickerson to move on an idea Etsy had long been considering: creating an open application programming interface, or API -- a set of programming tools that makes it easier for outside developers to build new applications using Etsy's code. "Feature requests rise up that we aren't always able to build as quickly as we'd like," says Dickerson. With an API, it would be even easier for Etsy fanatics like Lievano to create new features.
Large tech companies such as eBay and Salesforce.com have long offered such tools to third-party developers. But use of these programming tools has accelerated recently, says John Musser, who runs ProgrammableWeb.com, a website that tracks the use of APIs. More than 500 were launched in 2008, about as many as were built in the prior seven years combined, according to Musser. The microblogging site Twitter, for example, receives twice as much traffic from third-party applications as it does from its own website.
