Online, demographic targeting is already light years ahead of traditional media-- what Yahoo Sales Chief Wenda Harris Millard famously calls "spray and pray" marketing.

Even so, the near future should bring exciting new advances to improve targeting and increase advertising spend ROI.

Power combinations: Ad networks will continue to extend the power of DT by combining it with other technologies. For example, by purchasing behavioral profiles of users who have historically visited sites that fit their demo, advertisers will then reach consumers through other sites and other marketing channels like email.

New technologies: At present, no ad network can reliably separate men from women and serve different ads accordingly, but that is sure to change on the technology side across different networks. (Specific Media, for example, is developing a "Demographic Prediction System.")

Next: Where to go from here