There is one thing you are all missing which is really killing you guys as affiliates.
I run a business where the traffic we generate carries a cookie whichs tells me the source of the traffic. (perfectly normal you might say)
However when a punter visits the site who has no cookie, we log the sale with a "no cookie" referrer. (again perfectly normal you might say)
The problem is, the more money I spend buying traffic the bigger the business gets, but the sales are not always cookie'd traffic. My non referrer no cookie traffic grows every month.
(and this is a site with virtually no serps)
So my only conclusion is that modern browsers like IE8 (and some privacy/spyware/virus software) with their "In Private" features having a considerable impact and removing the cookies which are the lifeblood of the adult sponsor/affiliate industry.
Believe me or not, it is up to you, but I see the stats everyday, and this is the only conclusion that I am left with.