Why does the Windows registry exist? [closed]

Answer 1

• Each application doesn't have to reinvent a config file format
• You can easily use the registry in kernel mode code

As mentioned in the Old New Thing article cited by Bastien:

• The system can handle concurrency issues for you
• You can ACL registry keys

I would also mention that many *nix frameworks have reinvented the registry... Like gconfd on GNOME.