Go to Rapidshare and upload any files you want. In theory you can use Megaupload as well but I have not tried it personally. Then grab the download url and paste it into the footer of your website in plane text. If your website is indexed and gets spidered frequently all you need to do is wait. What happens is that all those Rapidshare search engines pick up on the new link and index you. Now every time somebody searches for a keyword that happens to be on your page, they will be redirected to you. For example I had a page selling Bookmarking Demon. After adding the Rapidshare link to the footer I started receiving visitors from Rapidshare search engines looking to download Bookmarking Demon. Some keywords will bring you more traffic than others. I think their scripts scrap Google for pages containing Rapidshare links and then all the other smaller websites scrap Rapidshare search engines using their API keys etc.