What is your competitive differentiator? This is what the marketing guys are asking all of the time. Sure you provide a users IP address, or even their browser info, but do you provide a chicken?
And who is king of the roost? Well I don't know for sure, but my money is on IP Chicken. (Though IPGilaMonster might be catching up fast)
Props to Smitty.
Disclaimer The opinions expressed herein are my own personal opinions.