Though the primary source of revenue model for such blogging platforms has been Advertising revenue on user generated content though likes of wordpress have also benefited from offering blogging tools,hosting platforms etc.
The problem with web 2.0 content generated is lack of trust in quality of same as compared to editorial driven and hence most of the monetization ideas tend not to come in effect.
Keeping in mind how the publishing industry is suffering due to inability to refresh content and recent non-fiction piece of work getting traction has originated from blogs,online journals there is clear case with some one coming up with online trading platforms which let people monetize their content beyond digital advertising revenue. If a blogging platform can evolve to syndication service where we have publishing house on one side and the blog owners on another and create marketplace for increasing yield in auction scenario can help monetize reminant content which doesnt see day of light in offline media due to editorial limitation and vice-a-versa gain content in shorter lead time to meet issue goal.
The blogging platform can also evolve from various services like ranking the content,acting like editors and help improve price point at which it gets monetized or sold. Other services could be ranging from translation to other languages etc.
The scope for such platform is immense and some structure to this business model can help create unlimited scalable platform which would could become a technology services driven business.
Update: Associated Press does have a platform of sort for professional content being generated and now they have opened it up for Amateurs as well.
Found out about it at Techcrunch : http://www.techcrunch.com/2009/04/28/associated-content-raises-6-million-for-publishing-platform/
Looks like business model being thought in India are already in implementation in US