File Sharing, otherwise known as Peer To Peer. (P2P)

[tashi]

While P2P programs allow the creation of a network and enable you to connect with other users to upload or download material in a fast efficient manner, (often games, music, and films), using P2P is the cause of many infections.

File Sharing Programs are not to be confused with the actual files one uses a P2P program to upload/download.

Update:
Please see Post #3 below.
http://forums.spybot.info/showpost.php?p=218503&postcount=3


None of the files you download can be guaranteed to contain the content as described by their name.

Indeed many can and do contain viruses, trojans or spyware; especially as file downloads are typically from unknown sources.

Of course users should have an up to date anti virus program installed, but malware writers may use methods to circumvent security programs.

If you have downloaded cracks-warez-keygenerators, the odds are you already have an infected computer.
Even visiting such a site can give your computer multiple infections.

Your computer may then be exploited and act as a zombie or server of spam and malware to infect many others, often without your knowledge until your own system grinds to a halt.

Other people, using a peer-to-peer file sharing program, can access, retrieve and put files on your hard drive.

If you insist on using P2P.

• Set up the file-sharing software to limit others access to your private files.
• Do not put personal files such as medical, banking, tax, correspondence, address books or other sensitive information in the same folder as files that are shared via your P2P software program.
• Prevent the file-sharing program from automatically opening; especially if you have an always on connection which may allow others to copy your shared files at any time.

Many entertainment files infringe the copyright laws and if you share them, knowingly or unknowingly, you are putting yourself at risk of prosecution. The fact is the Recording Industry Association Of America RIAA has sued.

Update:
Wired. June 18, 2009.
$1.92 million fine

P2P
http://en.wikipedia.org/wiki/Peer-to-peer

[tashi]

Open source programs are distributed under a license that allows for repackaging and redistribution.

In a nutshell this means the program could be modified by unscrupulous parties to bundle malware and then passed off as the original application.

Download programs from the official web site of the program's developer.

Of interest:
Resources for open-source developers and a directory of in-development open-source software.

[tashi]

Many people seeking help in the malware removal forum have a computer infected by the practice of P2P file sharing.

Our new policy:

• If such programs are on your computer you will be asked to uninstall them and help withdrawn should you not agree.

• Please be aware that Tools used during the cleanup will probably detect these programs and remove them.

• Once the machine is clean, if you return with another infection contracted by the use of P2P programs, volunteer analysts may refuse assistance.