[The Illuminatus]

If you manage to hack a forum, change user administrative privileges to yours for a little while. Get into the database and download all the SQL files from the DB. When you do that upload all the stolen files to your web host and bam, you've stolen and replicated another website.

[Krypto.]

PHP and SQL DB's are server side. This means that without a shell or some sort of FTP, you have no way of taking it off the server. HTML/JS/CSS on the other hand are all handled in your browser and can be stolen.

[miles2k6]

Speak to Anonymous, he'd probably help.