There are many free downloading websites on the internet like the one named Torrent. But there is one thing common among all of them---they all will invite you to Sign Up of Register, before providing you the downloading facility of any searched file---video, music, photo, pdf ebooks or whatever. But there are other websites also on the internet which do not need such Sign Ups or Registration pre-conditions. I want to know that why this difference ? And why it is needed to Sign Up in sites like Torrent ? Is there any risk ? Generally what they do is, first they tell you to download their own DOWNLOADER software. But I have heard that these downloaders sometimes contain virus or malicious file which damage your operating system in computer. I have even heard that sometimes those Downloaders contain spying software, which take away vital or confidential informations from your computer.