When you use Apache with the mod_userdir module (most distros set this up by default), you can specify a folder for that user to have their own webspace. By default, this is called public_html. If you put an index.html in there, and connect to your machine with a browser, using this URL:
http://your.name.or.ip/~username
your page would come up (as long as apache was set correctly - you might need to add another /). You might notice a lot of ISPs give you your own webspace using a similar URL.
