The deal will see IBM linking directly to eBay on the IBM.com homepage and the two companies exploring a joint marketing campaign for print and television.
EBay will implement IBM's WebSphere Web infrastructure software for its auction site as part of a broader upgrade effort. WebSphere is "middleware", software designed to run on top of an operating system but itself works as a platform for running other applications like e-commerce software.
Another element of the deal calls for IBM to expand its shop in eBay stores, a section of the site eBay launched in June as a more traditional online sales venue. Most of the sellers in eBay stores to date have been small businesses with relatively long-term ties to eBay.
Although eBay is noted for low prices, IBM's price listings are not significantly different from those offered on the high street or on its own Web site.