I thought that Chris Charron, an emerging technology consultant, made some great points. Here's my summary.

Online advertising model looks a lot more like newspapers (with 18% fees, 82% ads) than like magazines or TV/cable/satellite (stats from Forrester Research). As users create content, they are less willing to pay for it. Some kinds of content are neither the kind of content that people will pay for nor good venues for ads. News may be one of these. These kinds of sites need to consolidate, migrate to the public sector, or come up with some other solution. User-generated content can be hard to get advertisers to support, since they don't know what the content will be and whether it will be appropriate for their ads to be next to. (Rating content can help.) Viral marketing uses the information flow of the Net to its advantage. Net marketing was originally based on impressions in a passive environment, but we're moving to performance-based payments, where advertisers pay for click-throughs. JetBlue lets customers upload pix and stories about their trips -- corporations can get their customers to create their ads for them for free! The Internet and other connection technologies can be scary (loss or identify, truth, and reality), but we gain multiple identifieds, truths, and realities).