Deeper referrer tracking
 

It would be nice if browsers would tell you more specifically where a person came from. For example give the last 3 locations the visitor came from and not just the last 1.

site1.com -> site2.com -> site3.com -> yoursite.com

Visitor was on site1 and clicked something which sent them to site2, they click something and went to site3, and from site3 they were sent to yoursite.

Let's say site3.com is sending you sales. If you could figure out where site3's converting traffic is coming from (site2.com), then you could try going to that site for traffic also. And eventually work your way to the best sites with the best traffic.

And that is why most affiliates try their best to hide where their traffic is coming from :)