What is the Dedicated Server Colocation Good For?

Dedicated colocation servers can be used in many ways:

ISPs to host Web sites for their customers. You pay a flat monthly fee. You can add as many domain names and web sites as you want;
Regional or national providers who want to roll out services in St. Louis.
Dedicated Web servers for high traffic Web sites
Dedicated Chat servers
Dedicated IRC servers
Dedicated FTP mirror servers