John Battelle builds upon Cost Per Influence with his expertise in publishing to account for a Sell Side Advertising model: a very interesting idea that flips current advertising models upside down. In essence, this new model for online ads reverses the relationship between publishers and advertisers. Read the whole thing.

But one issue, the initial origination of ads. In Sell Side Advertising the ads are cast out, perhaps through del.icio.us like directories and ad networks like BlogAds or from advertiser sites themselves. But is this first source influential? Are they in a position to set the initial price?

It may mess up the elegance of how John’s description, but it may need a Buy Side component, at least to help set clearing prices. Much like what BlogAds does, blogs could list a rate for hosting an Ad. Advertisers could offer an Ad, if its approved or sponsored and posted, then the chain begins.

If you combine both, the Ad network could function as a Market Maker — standing ready to offer a price on both the buy and sell side to enhance liquidity. But again, starting simple is very good.

John also pointed out a key attribute of this concept to me over the phone — putting publishers back in the decision making process also serves to encourage socially responsible advertising.

In related news LinkedIn is serving User-Sponsored Links and Blogger is offering a revenue sharing program with Bloggers.