If forced to point to a single effect of Web 2.0 that is causing major ripples throughout the media landscape, I would have to go with User Generated Content. Ad spending on sites like YouTube, MySpace and Photobucket is expected to exceed $4.3 billion by 2011. That's about 330% more than the approximately $1billion that'll be spent this year.

But not everyone is drinking the UGC Kool Aid. In his new book, The Cult Of The Amateur, Silicon Valley enterpeneur, Andrew Keen, argues that what the Web 2.0 revolution is really delivering are "superficial observations of the world around us rather than deep analysis, shrill opinion rather than considered judgment."

By undermining mainstream media and intellectual property rights, Keen argues, it is creating a world in which we will “live to see the bulk of our music coming from amateur garage bands, our movies and television from glorified YouTubes, and our news made up of hyperactive celebrity gossip, served up as mere dressing for advertising.”

There's a scene in Michael Crichton's Jurassic Park where mathematician, Ian Malcolm, in commenting on a technology that enables dinosaurs to be cloned, says, "Your scientists were all so preoccupied with whether or not they could, they didn't stop to think if they should."

Is Keen right? Just because UGC can be done, should it? With all the ad spending on UGC sites being forecast, it might already be a moot question.