Fred Wilson covered the validity / opportunity / challenges associated with advertising as a business model in a recent post. The whole thing (and the comments)

Fred Wilson covered the validity / opportunity / challenges associated with advertising as a business model in a recent post. The whole thing (and the comments) are informative but here's my high level summary; - Huge difference between ads that are sold (niche) vs ads that are bought (scale). - It takes millions of users a month to be successful at scale. It takes a great sales team to be successful in a niche. - The absence of scarcity in online and mobile advertising creates structural downward pressure on CPM. http://www.avc.com/a_vc/2012/12/mba-mondays-revenue-models-advertising.html http://www.avc.com/a_vc/2012/12/mba-mondays-revenue-models-a...