Yahoo! has signed a definitive agreement to acquire Dapper, a technology platform providing dynamic display ad creation and optimization.

Yahoo! is already the largest and most successful force in display advertising, but the strategic addition of Dapper will enable our advertisers and agencies to quickly and easily build dynamic ad creative, leveraging data to automatically show the right product, offer, or message with each impression.

Smart Ads continue to be a critical component for display advertisers. Dapper’s capabilities, combined with Yahoo!’s already deep consumer insights, will help Yahoo! more efficiently deliver dynamic and personalized ads for customers across more of our network and will accelerate the adoption of Yahoo! Smart Ads.

Yahoo! currently partners with Dapper, along with others in this space, and owning the technology will help us deliver innovative solutions to an even broader range of advertisers and integrate dynamic ad serving into key Yahoo! properties.

Dapper was founded by Eran Shir and Jon Aizen in 2006 with a vision to transform display advertising with personalized, relevant content. Read what Dapper co-founder Eran Shir has to say: http://shir.posterous.com/why-did-we-sell-dapper-to-yahoo

We expect to complete the acquisition in the fourth quarter of 2010.