There is only one way to stop spam, and that is to remove the incentive. Technical solutions help, but the determined will always route around blockades.
Now, imagine if you ran a search engine, and you had access to the actual sales data from websites. In return for this sales data, you may give a boost in ranking to those sites with a good sales record, because those sites have a history of delivering what the consumer wants. Will this remove the incentive for affiliate-related spam? No sales record = no serp position on commercial queries = no commision.
Ok, that argument is a bit of a straw man. However, this issue is being discussed around the web, and it’s only a day or so before we see what Gbuy looks like. What data will Google be collecting, and how will that data be integrated into search and advertising results? What will the effects be?
For the record, I don’t think affiliates are going anywhere. Affiliates are often better at web sales than the merchant sites, and cover areas that the merchant sites deem unprofitable (for them). Sales data can’t weigh too heavily, or you’d remove much of the sales funnel (i.e. product information, comparison, etc), and therefore decrease the utility of the search results. Then there’s the wider issue of possible fraud.
All speculation, of course. It will be very interesting to see what shape Gbuy takes, eh.