Why is demography so important for marketing and advertising?

How big is the global market for brand advertising as opposed to that for direct marketing?

• Facebook COO, Sheryl Sandberg, is reported to have claimed that brand advertising corresponds to 90% of the global advertising industry and that Facebook is better positioned to address that market than Google (which has most of its revenues based on search advertising which is actually direct mareting taken online). http://bit.ly/9NHqPZ Is she right about the size of these markets? By the way, prior to Facebook, she was the head of global online advertising sales at Google. This is a follow up question to 

• Answer:

  If you're talking online and offline combined, every metric I've seen shows brand marketing and direct marketing to be about 50/50. That includes promotions and other forms of direct marketing like telemarketing and direct mail on the direct marketing side. Online, according to the latest IAB numbers, search marketing is 47% of total spend and display, rich media, and video (a proxy for brand) are together around 36%. So you have to know what Sheryl means by "global advertising industry" to judge her 90% comment. On the broader "marketing" split, she's wrong, but on some definition of "advertising" her numbers may work.