So far, I have only installed referral text or button links for AdSense, Firefox with Google toolbar, Picasa, Google Checkout and Google Pack. However, in my report, I see reports for referrals for other products which I have never installed. This was after they implemented referrals 2.0.
I think if Referral 2.0 have a way to optimize their referral links, probably for the optimal earning potential. However, if they want to do that, what they should do is to display all 3 referral links, but replace one with another referral link which they sense may have a higher earning potential.
However in the case of Guide to Egypt, what I saw was only one referral text link, that is "Egypt Market Research Report". The other referral text link I included wasn't displayed. I think this is unwise of AdSense and I shall report this to AdSense Support and see what they have to say about it.
Things are not static, and not only that, what is displayed may depend on the location of the visitor, so I show below a screenshot of what I saw when I visited the blog:
