semi- off topic
...Everything you do on the internet is tracked by your IP address...
not exactly...the only way anyone (or any other computer) can connect any given IP address to an individual is if your ISP wants to give it to them (usually only done by subpoena)...
internet cookies sometimes use IP addresses for things like "keep me logged in" etc... or keep you from voting twice on the same polls etc...but not all cookies use IP addresses
The way computers communicate with each other across most networks is via IP...each computer (or node) must have a unique identity so whatever is requested can be served...i.e., [example] whenever a link is clicked...the browser sends a "request" to the server...if the request did not include a return IP address...the server would not know what computer to send the file(s) to...so you could view the web page, picture etc...
Most ISPs use a system (DHCP, or PPoE) in which their servers assign an IP address to your cable or DSL modem etc...if you re-set your modem 99.9% of the time your IP address will change...back in the days of dial-up...your ip address changed every time you dialed in)...now days if you want to change your (modems) IP address just reset your modem...
...because the modem only has one IP address is why a router is needed if you have more than one computer connected ...the router has its own DHCP server that assigns each computer their own (sub) IP address...
...regardless of how many computers you have connected to the internet...all the rest of the world sees is the IP of the modem...not the individual computers IP address.
if you don't liked being "tracked"...I suggest turning off cookies...or at least 3rd party cookies...
just to be noted...each ethernet adapter whether it's wired or wireless...has another type of unique identifier that never changes and can be used to isolate any single computer on a network...it's called a MAC address (nothing to do with Apple)...this identifier is hard coded into a chp that is acomponent of the network adapter...unless you are running a very old unsecure system it is very unlikely that anyone outside of your local network can ever obtain your MAC address...