Because online sellers advertise more heavily, and their traffic is of better quality, they should unit together and trade traffic amongst themselve. That makes the advertising dollar worthwhile. Agree?

Lol, the way you put that brings back memories of being at school, getting my homework

It's a good idea, as long as it doesn't end up causing the sites to compete with one another. For example, if a network were created that consisted of the websites for Best Buy, Office Depot, and Staples, a higher proportion of people than usual would start buying from whoever is the cheapest, thus drawing traffic away from the other two.

Well, competition is not that a big problem, at least not for me. I run a fabric website, and nobody else sells cheaper or has the same selection. I put ad code on my website, and it shows a lot of related fabric sellers' websites. I'm not worried about it. As long as my products are unique and have good prices, the rest of the traffic (who are not buying from me anyway) can make me some money, or at least get me some traffic back.

Interesting coincidence--I manage http://www.rainbowsendquiltshoppe.com (one of my biggest clients, in fact), and they have over 18,000 bolts of fabric in stock. Right now their online store focuses more on notions than actual fabric... would you care to exchange links?