Software keyloggers (also known as key-loggers, key loggers, keystroke loggers, key recorders, key trappers, key capture programs and under a lot of other names) belong to the group of products that make it possible to control the activity of PC users.

Initially, software products of this type were used only to write information about keystrokes, including system keystrokes, to a special log file. The person who installed the program used to study this log file later. A log file can be sent over the network to a network drive, to an FTP server on the Internet, by e-mail, etc. Lately, software products named like this have acquired a lot of additional features - intercepting information from windows, intercepting mouse clicks, making screenshots of the screen and active windows, registration of all received and sent messages, monitoring file activities, system registry and queue of jobs sent to the printer, intercepting sound from microphones and video from webcams connected to the computer, etc.

REFOG Keylogger, Activity Logger, Boss - Everyware, Ghost Keylogger, Hook-Dump, lamBigBrother, Invisible Key-Logger Stealth, iOpus STARR, iSpyNOW, KeyCopy, KeyKeeper, KeyKey, KeyLog, KeySpy, Keystroke Reporter, PC Spy, Perfect Keylogger, ProBot, Realtime Spy, Spector Pro, SpyAgent, SpyBuddy, WinWhatWhere Investigator is an example of well-known keyloggers. There are hundreds of such products in the world today. They differ in functionality, usability, report completeness, invisibility level and the level of protection against detection and deletion.