In an effort to disguise illegal software from admins, or simply just to shorten names with an 8.3 filespace, people change the names of the files.

Often these illegal software packages have a text file along with it, so a group of people can claim responsibility for making the pirate copy of the software.

This file is called and named a .nfo file, and usually also contains the number subsitution for letters found in the filenames. This then followed through onto IRC, FTP and Web sites.