Right now I'm on a shared hosting plan and its fairly easy to use. At some point I'd like to switch to a dedicated server - but how much do you need to know about web server administration to run your own dedicated server. Are they managed just as a shared account, but it is just on its own server, or is there more administration that has to take place?

And what are the real advantages to having a dedicated server vs. shared plan, or a vps?