Paid-search leader Google has dominated technology headlines in recent years, overshadowing older and more entrenched firms like Yahoo and Microsoft. But a new strategic alliance between Yahoo and eBay appears ready to shift the competitive landscape.

According to a recent announcement, the two Net giants have entered a multiyear partnership that will enable the firms to draw upon each other's expertise in online advertising, payments, and communications. Yahoo will become the exclusive provider of graphical advertising throughout eBay's Web site and will provide some search-generated ads. In addition, Yahoo's brand and search engine will be blended into an eBay toolbar that has been downloaded by 4 million users.

As for eBay's contribution to the partnership, the Web-based auctioneer's PayPal service will become the preferred payment provider for purchases made on Yahoo's site, which offers shopping, auctions, and subscription services. Moreover, eBay's multibillion-dollar Skype service will be used to build a phone-based marketing vehicle through which advertisers will connect with prospective customers.

San Jose, Calif.-based eBay currently boasts nearly 200 million users at its Internet auction site. Sunnyvale, Calif.-based Yahoo is the world's most trafficked Web site, with 402 million users.