File extensions must the be one of the worst things about computers and there is no escaping. Those 3 letters after the period determine what application will handle your file. If you’re in any doubt as to what file format that extension relates to then this will be an extremely handy resource to have nearby.
Not only do they list what extensions belong to what applications but they have a handy tool that will clean up your registry and fix missing file associations. All to often you’ll install a new application which takes over a file association only to uninstall it later and find you’re no longer able to open your files.
Whilst the application on offer might only be really useful when things really break down their database is invaluable as a file extension lookup.