Welcome to the Virus Encyclopedia of Panda Security.
Cookies store information that can be used for several purposes:
These uses are not, in theory at least, malicious.
Though it does not pose a risk by itself, malicious use by other software could threaten affected users' privacy, as cookies can be used to create user profiles with information that the user is unaware of, and sent to third parties.
Additionallly, some cookies can be created by certain spyware or adware programs when they connect to their own websites, or also by some advertising banners.
WWW-porno does not spread automatically using its own means. It needs the attacking user's intervention in order to reach the affected computer. The means of transmission used include, among others, floppy disks, CD-ROMs, email messages with attached files, Internet downloads, FTP, IRC channels, peer-to-peer (P2P) file sharing networks, etc.