IP's... Different #'s = Is it that simple?

[Donna]

I check and recheck my IP address, constantly, to ensure that different setups on different sides of the modem (usb port/ethernet port give different IP's, which go to separate computers...) So I always confirm and re-confirm that my IP's are different.

Is it that simple? Is a different # sequence all that I need to see? Is there any way that certain numbers can show Ebay/Paypal that I'm somehow linked? Or is what looks different to me look different to them as well?

Thanks to anyone who knows in depth how these IP #'s work....!