title: Purpose of a2ensite and a2dissite
body: <p>I just set up my first Ubuntu dev environment and was wondering why there are 2 direcotries called sites-available and sites-enabled. After some reading I stombled acress a2ensite and a2dissite. Also I read that I have to put all my vhost stuff into sites-available and then enable it through that command.</p>
  
  <p>Ok, tested it, and it works. I'm used to mac, and there I just created an vhost and the site was "enabled". There was never such a thing like disabling and enabling a site. I've read , that it is nice, because you can disable a site when it is broken very quickly...</p>
  
  <p>But I don't get it. What's the purpose of the whole thing? How should it help me? Why should I use it? If there were something like a maintenanc.html for each site which it creates an link to, it would might make some sense, but since it doesn't do such a thing but just creating/deleting symlinks, i really don't get its purpose.</p>
  
  <p>If i disable a site, the site isn't really down, it just servers the default vhost. Which actually makes sense due to the principle of how apache handels the whole stuff.</p>
  
  <p>So, what is it, which I don't see? :)</p>