A URL may consist of sever things such as a service identifier, hostname, a path, a filename and a querystring.

Service Identifier:

          http://
          ftp://

Hostname:

          www.enigmagroup.org

Path(folder):

          /forums/

File:

          index.php

And in some cases a query string or anchor.
This is a query string:

          ?page=search&name=Hobo-Euan

Altogether now:

          http://www.enigmagroup.org/index.php?page=search&name=Hobo-Euan

Also you may have the http server running on a diferent port so let's say the site we just visited was running on port 1337 it would be:

          http://www.enigmagroup.org:1337/index.php?page=search&name=Hobo-Euan

Some interesting ports that you can try visiting with what i showed you.

HTTP by default runs on port 80 and is what your currently viewing by.
SSL by default runs on port 443 and is what you would use for online shopping.

Thanks for reading my article.
HoboEuan