I wish I had more details for you, but the idea of Amazon getting into the online advertising game is pretty interesting because their personalization and recommendation engines are well proven and generally liked by Amazon members and the idea of using that tech to serve ads is compelling and pretty unique.
Job Title: Online Advertising Opportunities
Description: Over $20 Billion will be spent in online advertising in 2007 in the US alone. And by 2011, those numbers will more than double. Amazon.com is continuing to build out its Worldwide Online Display Advertising business to tap into this growing market. We plan to build next generation advertising products by leveraging Amazon’s world-class personalization technologies, unparalleled customer data and engaging video content. As part of our growing team, you will work closely with internal stakeholders, advertisers, agencies and senior management.
EDIT: here’s a link to their site, which lists all the positions.