>Ok what are the other things (a VPS server can do)?

VPS = Virtual Private Server
An operating system with virtual paths to hardware.

A Dedicated VPS Server:

> Control panel
add/remove domain based web sites
add/remove email accounts and addresses
add/remove mysql db accounts
Host many small web sites on a single server!
Great for resellers

> Dedicated CPU, RAM, & drive space
reliability, speed, etc.

> Dedicated Operating System
custom settings for email, applications and custom software
server will only host you and your clients

Scale by adding more VPS servers to your account, example, setting up a dedicated mysql vps server can drastically reduce the load of your web server, making your site(s) faster.

Travis