Where is the investment opportunity with ads? Is it the Aggregation of attention?, eyeballs? It's not about the advertising. The real value in the intelligence of users, not eyeballs? ... that's where the money is. [0]
The way I look at it, UGC (user generated content) really just another form of advertising? [1] So when you write content (commercial info about a product made for profit) I'm really writing an ad, my ad. I value readers & their ideas and as such don't want to distract them with freeloader advertisers.
Reference
[0] Dave Winer, 'How to Make Money on the Internet v2.0'
http://davenet.smallpicture.com/2001/02/13/howToMakeMoneyOnTheInterne.html#4
[1] Dave Winer, 'How to make money on the Internet, 26 November 2006, MP3, 10.6 Mb, 10 min.'
The basic premise is the same as the one mentioned in Biz 2.0 magazine: If there are no ads on your site, you will not make money off of it. If there are too many ads on your site, nobody is going to click on them.
Daniel, thank you for posting this since before reading it, I did not have any factual data to back my claim :)