DeeCee - 7:19 pm on Feb 29, 2012 (gmt 0)
On "static IP", FYI.
You and your colleagues are probably all running behind a NAT (Network Address Translation) router, which translates a single IP from your ISP to multiple internal ones on your workstations. So you all present the same exact IP address to the outer Internet (the router's external IP). Leaving only cookies and similar personalization to change the content if it should change. Check your internal workstation IP.. If it is a typical 10.* or 192.168.* type address, you are all using IPs that cannot be routed on the Internet and must be translated.
In today's world, even if you do not pay your ISP for a dedicated static IP from your service provider, on cable and other fixed service providers, your IP address on an always-on type ISP is in reality as constant (different from static) as can be. It is merely that you cannot advertise it in DNS as such because it "could" change at random times. This notion of course depends on the ISPs way of operating.
The IPs on my internet servers are really static, as in they are fixed assigned and announced in my DNS.
My home IP for my router, hiding a bunch of servers and workstations behind it, which is allocated by DHCP from my ISP and specifically defined as non-static is still fixed assigned to my house, and in fact has not changed for I believe 6-8 years at least. It is always the same. I even 3-4 years ago put it into my own DNS, so I can access test servers I have at home by that external IP.
This is why IP based location tracking works. The ISPs upload the list of IPs and their "approximate" location to the location providers.