Yesterday I was thinking and posting about sites with an API like Flickr, del.icio.us, and Google. If you don't know, an API is an interface to data. Flickr's API lets you post pictures using your own tools without having to go through their site, for example. APIs let you develop what Tim O'Reilly calls the third type of application, data applications. Data apps are applications that take advantage of data. Amazon isn't the biggest book store because they have the best software applications, they're the biggest because they used the data in important ways. It's much more useful to go to Amazon.com to look at a book than Barnesandnoble.com because you'll find 10 times as many reviews and pointers to other books and other useful things they've done with their data that B&N hasn't done. The reason you see Amazon search boxes and tools all over the place is that Amazon has a really good API.

Getting back to the point, I was thinking about APIs and I realized that I don’t know anything about an ebay API. I didn’t think there was one, in fact. It turns out there is one but it’s stupid. Well, maybe it’s not stupid but ebay is because you have to pay to use it. It costs $100 (at least) to get to use their API. This is a monumental mistep. By trying to “recoup costs” (their phrase) on the use of their infrastructure by the API they’ve completely cut themselves off from any network effects that sites like Flickr take advantage of. If you let people into your system, they’ll do cool stuff that gets you more attention and more revenue. I want to write a plugin for MythTV that displays a message on screen if an auction you’re watching is ending soon. I think that’s a pretty cool idea and would probably make me more likely to use ebay but I can’t do it because it’s not worth $100. Maybe if I did tons of ebay business I would think about it. But probably not. But what I can do is write a Flickr plugin because they let me into their data. If an auction site comes along and lets people hook into their data, they’ll expand the range of applications people can use their site for and immediately gain a lot of mindshare.

But I like ebay so I hope they realize that things like abusers are a small problem in comparison to the benefits of letting bloggers put ‘Here are the 10 newest auctions related to my content’ boxes on their sites. Or letting somebody write a ‘Hey, your auction is ending in 10 minutes’ test message generator. Or an ‘Ebay Zeitgeist’ app that shows Flickr pictures related to the 100 newest auctions with ‘cat’ in the title. Etc., etc., etc. A geek can dream.