I don't think so, one of the sites has a shopping cart that depends on cookies ie you can't buy something unless a cookie is set. I am talking about ROI tracking ie tracking those that bought something, not just incomming traffic. When they arrive the system collects the referrer field, key words etc and stores it; when they buy the system adds that info to the data about purchasers. The problem is that up to 50% of purchasers have an originally empty referrer field. I go look at the raw logs (well my Programmer does) and see a lot of empty referrer fields.
use a Tracking URL for your advertising sources.
Yep, doing that. Our tracking system picks them up for Adwords and Overture, but also monitors non sponsored purchasers.
Are we talking about the IP field or the referrer field?