I saw someone say in some forum somewhere that Google was going after those sites in which the link seller's motivation was the passage of link value (i.e. PR). That's what has been sticking in my craw for a while but I hadn't had the time to let it simmer and gel in my head until now.
In other words, WTF? You have to be kidding me. The motivation of a person selling links, the LARGE majority of the time, is much simpler than that. The seller is monetizing his site. Period. And if the buyers are concentrated in a handful of places, namely link brokerages, then the seller sells in those marketplaces. Why? Because that's where the money is.
The seller doesn't give a hoot about passing link value. The seller has ad space to sell and wants to sell it. The seller would be silly to try to sell his ad space in a marketplace in which there were no buyers. If the marketplace changed, and all the buyers moved from a system in which links were automatically followed to a system in which links were nofollowed, the seller would move to that marketplace as well. The seller is only selling his wares in the markets in which the buyers congregate. That is the sole motivation of the seller.
The buyers, on the the other hand, now that's a different story. The buyers' motivations are MUCH more likely to be centered around the passage of link value. That is why the buyers line up at some link broker sites and not others. They only want to buy followed links, so they hang out in the marketplace that brokers those kinds of links. The sellers see them all there, and follow (no pun intended).
This misconception that sellers deserve punishment because they are motivated to game the system is cockeyed to me. Link sellers merely have ad space to sell, and would happily sell in a completely different market, such as a google-approved system, if that market was a viable one. Gaming the system, I believe, is not on the average link seller's mind, but is likely on many link buyers' minds.
Well, that's my opinion, anyway.