Quote Originally Posted by spongebue View Post
IP addresses are what is used to determine uniqueness. Company networks have a better chance of not sharing an IP address if they're on different computers. What's My IP Address? Networking Tools & More can give you the number that we'd see. Keep in mind, your own IP address must be different than those that referred you, too

Kerry, please correct me if I'm wrong here, but I think this should be about right.
I do understand Coasterpan's concern here. Some companies/airline have a single proxy server so that all employees, when they are at work, come from the same ip address.

Update: I've found a way to make exceptions for situations like this. Already accounted for the Delta.com proxy, for example. Feel free to let me know if you think you are being unfairly dinged on your referral count.