Unique Visitors = 1/10th of Unique IPs?
Max Fomitchev submitted a little blog entry where he proposes that the ratio of unique IPs to actual unique users is 10:1. This flies in the face of the numbers you usually see attached to these sorts of things. I'm not sure about the logic he uses to come up with these numbers either.
I think anyone in the tech sector knows this already. It's pretty common knowledge that people surf from multiple IP addresses. How about a solution instead? How about adding MAC addresses to stats, or modem_id's (whatever the equivilent to them is a to a MAC) and have webbrowsers send that data too then stats applications can have something more unique to identify a unique customer by than an IP address.