There's a certain website, where I purchased a CD and In return I was given something else. The CD was only 4 dollars, but what you get in return is 20 dollars. So I wanted to do this offer again. I changed my ip and went on my laptop. Basically, I had a different ip and computer, how could the website possibly realize who I was? And oddly enough, It didn't let me do the offer again. How the hell do certain websites recognize who you are, even after changing your computer and ip?