How do I change the computer's ID on my Mac?

Can a website like Ebay track my MAC address? I know they can track IP addresses but can they ID me from a MAC

• Can a website track me by my computer's MAC address? is that possible? I already know that they can track my computer from my IP address but what is the deal with MAC addresses. I know these addresses are suppose to be hardware to Harware communication but I've been reading about people concerned about having their computer tracked through their mac address. The reason I am asking this is that Ebay has a new policy where they are putting permanent cookies on computers. I want to know why this is legal and how are they doing it. If they are doing this throught the IP or cookies, that's not a problem to me as I know how to change that. However, I know Mac address are connected to the hardware so, that's not too easy to change. If anybody knows anytrhing about MAC addresses and tracking, please respond. Thank you.

• Answer:

  My knowledge of the tcp/ip protocol stack is limited, but as far as I know, the only devices that know your mac address are the routers/switches directly connected to your machine. Anything outside of that only knows your IP. As for the usual cookies, assuming that their using normal http cookies, then they're only 'permanent' in that they never expire. You can get rid of them by simply telling your browser to delete cookies (how to do this varies by browser).