via www.brandingstrategyinsider.com/

The diversity of the 18-49 demographic certainly isn't new, and on the surface shouldn't be cited as a notable trend for 2010. But, when you stop to think about how different the media world is for an 18 year-old, relative to a 49 year-old, you might just be ready to step away from a target cohort that doesn't hold up. And every year, the divide between 'internet-raised' and 'television-raised' consumers becomes more profound. Just read 'Media Generations' by Martin Block PhD, Don Schultz PhD, and BIGresearch, and you'll quickly understand that today's 18-49 demographic cohort contains four different media generations.

A more finegrained means of target demographics is necessary.