.log files are usually simple text files that are used by many applications to hold a log of events. For example, when installing new software on your computer a log file is often generated to hold information on what existing files were modified and what new files were installed on your computer.

These files can be created by the operating system or potentially any application that is used on your computer.

Many web servers that supply web pages and web services generate log files. The data within these log files can then be used to monitor website bandwidth usage, as well as monitor visitor numbers and traffic information.