These are my notes from the session eBay Web Services: A Marketplace Platform for Fun and Profit by Adam Trachtenberg.

This session was about the eBay developer program. The talk started by going over the business models for 'Web 2.0' startups. Adam Trachtenberg surmised that so far only two viable models have shown up (i) get bought by Yahoo! and (ii) put a lot of Google AdSense ads on your site. The purpose of the talk was to introduce a third option, making money by integrating with eBay's APIs.

Adam Trachtenberg went on to talk about the differences between providing information and providing services. Information is read-only while services are read/write. Services have value because they encourage an 'architecture of participation'.

eBay is a global, online marketplace that facilitates the exchange of goods. The site started off as being a place to purchase used collectibles but now has grown to encompass old and new items, auctions and fixed price sales (fixed price sales are now a third of their sales) and even sales of used cars. There are currently 78 million items being listed at any given time on eBay.

As eBay has grown more popular they have come to realize that one size doesn't fit all when it comes to the website. It has to be customized to support different languages and markets as well as running on devices other the PC. Additionally, they discovered that some companies had started screen scraping their site to give an optimized user experience for some power users. Given how fragile screen scraping is the eBay team decided to provide a SOAP API that would be more stable and performant for them than having people screen scrape the website.

The API has grown to over 100 methods and about 43% of the items on the website are added via the SOAP API. The API enables one to build user experiences for eBay outside the web browser such as integration with cell phones, Microsoft Office, gadgets & widgets, etc. The API has an affiliate program so developers can make money for purchases that happen through the API. An example of the kind of mashup one can build to make money from the eBay API is https://www.dudewheresmyusedcar.com. Another example of a mashup that can be used to make money using the eBay API is http://www.ctxbay.com which provides contextual eBay ads for web publishers.

The aforementioned sites are just a few examples of the kinds of mashups that can be built with the eBay API. Since the API enables buying and listing of items for sale as well as obtaining inventory data from the service, one can build a very diverse set of applications.