Filename extensions for new apps

[teddymines]

When a software company creates an app that reads or writes files in a proprietary format, how do they pick filename extensions? The danger I see is that they might pick one that is already in use, and there would be a registry conflict. Of course they would stay away from the common ones such as .DOC and .TXT, but how about a .GWF or .KCF file?

Is there a registration process to "lock in" an extension with an application?

 

[Beau]

Not that I know of. It really doesn't matter anyway, considering you have the option of what program to use to open the file using right click.

 

[Nothinman]

Far as I can tell it's a free for all, with people avoiding very commonly used ones.

There would be no registry conflict, the installer would just just overwrite the old association =)