Date: 08/01/05 (WebDesign)    Keywords: php, css, html, java, web

Hi,
Sorry this is probably a rather dumb question but...
So I've been doing web design for quite some time now, using the basic design languages, html,css,dhtml,php,java. But I think I've kind of come up with an idea finally, a good idea, for a hopefully profitable website!
But one of the problems is, I need to be able to have users who can sign up and create their own accounts, such as signing up on LJ or Deviantart and getting your own page.
But I'm not exactly sure how to start creating such a thing. What language do I need to learn in order to accomplish that? so they'd have their accounts on a sub domain in essance. www.webpage.com/username
I've thought about using phpnuke or a forum based site but it just wouldn't work for my idea. I like Deviantart's setup. I would need something similiar to what they've got.
Thanks for reading my dumb question, I hope someone knows what I need.

Source: http://www.livejournal.com/community/webdesign/942600.html