The marketdroids at my company want to know how many people how many pairs of eyeballs have seen our site in a given month. I was wondering what techniques any of you may have come across. A straight up ip-count from the access logs is probably a gross over-estimate due to dialups and DHCP. Cookies might be a better way to keep track but still offers plenty of room for misestimation.
Are there any techniques any of you have come across, or know are used for this type of marketing information.