I turned off my modem last night and powered it back up a little while ago. SAME IP.
Bottom line...MOST people are logging onto the internet every day under the same IP. This IP is tracked by merchants, big brother, and other interested parties. When you buy products online, your IP is tagged and it's usually even listed on your order confirmation page. If you're doing nefarious activities online, they can easily track you. The theory posted several comments up that we can't be tracked because of our ever-changing IP addresses...is ridiculous. Of course they can.
“Let it not be said that no one cared, that no one objected once it’s realized that our liberties and wealth are in jeopardy.”
― Ron Paul