The directory is named "public_html". This is true if you would like to serve your site out of your personal, home directory (in the /home tree) with a URL like
http://www.something.com/~yourname or
http://my_ip/~yourname, where my_ip is the IP of your network interface to which the Web server listens.
For example, if your IP is 1.2.3.4, put an index.html file in /home/myname/public_html then you can access it at
http://1.2.3.4/~myname if your server is set up properly.
But in its foremost you need to make sure your Web server installation is set up in this way (if this is Apache then by default it should be though you should check yourself)