"Hovering"

"Is 'Hovering' the Future of Online Cause Marketing?" is an article posted on SelfishGiving and outlines a new online content services that allows for users to have deeper engagement with website content.  Essentially it takes the idea of hyperlink words and phrases a step further by providing readers with additional information when they "hover" over keywords or icons.  The difference is that you need no ever leave the page.

Peapod and Starbucks are just to examples of companies who use an the online service of Swoop.  And it isn't just generic information.  Users get information that is localized and personalized based on a user's history.  

It seems not only opportunity for companies to further promote their own company and products, but to join synergistically with other companies to promote brands and products.  It is, perhaps, the opportunity for "product placement" online?