Temporary Internet files are a cache of Web page content that's stored on your hard disk, enabling you to quickly view Web pages you've already seen, rather than have to wait when your computer downloads all the content of a Web page each time you want to see it. If your computer ascertains that you already have the Web page in the temporary Internet files folder and the Web page hasn't been updated since then, it gives you the version that's already in the folder. On the one hand, it's a convenience, but on the other hand, at some point you might find that your hard drive is getting pretty full, in the same way that you keep throwing stuff into your garage until there's no more room left for the car. In that case, it's time to clean up and declutter.
Depending on which browser you use (Microsoft Internet Explorer, Mozilla Firefox, Google Chrome, Safari, Opera, etc.), you have a different procedure for emptying your cache, and a bonus is that your browser will operate more efficiently, as well. If you have Windows 7 or Windows Vista, you'll find your temporary Internet files in your C drive.
Another reason you might want to get rid of your temporary Internet files is because anyone who has access to your computer is able to see all the sites that you've viewed if they look in your temporary Internet files folder. Be aware that even when you delete the contents of this folder, there are still traces left of the sites you've visited. If you really want to clean everything out, you may need more specific software to do a thorough job. You also have the option to leave some sites in your temporary Internet files folder, either because you plan on accessing these sites frequently or because it looks awfully suspicious to have absolutely nothing in this folder.