For any user that is using a P2P client for the first time, it will appear that they have got their hands on a great piece of software that gives them so much other software for free.
Unfortunately, it isn’t as clear cut as that– even when we consider the presence of copyrighted material and pornography disguised as innocent files, there is still the matter of malware, viruses, and spyware floating around all of these P2P filesharing networks, either with innocent names or hidden in zip files or the installation program of applications found on the network.
Word and Excel documents can include macros that can be used to run malicious scripts, and the dangers to your PC, data security, and identity security are considerable.
Why are standard documents available through these networks? The fact is, most users of P2P networks and client software don’t understand the full ramification of what they are doing. Many clients make available to other users the full contents of your computer, from the smallest GIF image found on a web page to financial spreadsheets, your family photos... and that novel you have been working on.
With these files logged and listed, it is a simple matter for a P2P filesharer to do a search for .XLS files and download a bunch of spreadsheets from users around the world.