This week everyone’s focused on Carol Bartz’s departure as CEO of Yahoo!. I’d rather talk about Yahoo!’s efforts to shore up its share of the online display ad market. One thing I like is the knowledge series that the company’s put together that promotes Yahoo! ad products and solutions by providing education, chiefly in the form of videos and stories that contain a wealth of expertise about what works in marketing today. Here’s one of those videos featuring the chairman of DDB. He explains how the ad industry can grow in a protean media space that’s increasingly focused on digital.