What even is an IP address?
An IP address is basically a little series of numbers that refers to your location and internet provider and account. It's unique to each person. So say, if someone here has another account and is posing as someone else, the mods would be able to tell. Why? Because the IP address would be exactly the same for both accounts.
So when people try to stuff the ballot box, the mods can tell cause the same nine sets of votes all have the same IP number.
When you post here, it's that little set of numbers next to the "report to moderator" link at the bottom of your post.