Joomla allows you to put the website in offline mode which basically means the website is no longer accessible to website visitors or search engines.
This is a really useful feature if you want to develop the website so only you can see it.
You can still preview the website when its in offline mode by logging into the websites front end using your user name and password.
How do I put Joomla into offline mode
Login to the administrator area
Select the system menu and global configuration menu
Select the site tab and change the site offline option to yes
You can now enter some text in the custom message box which will be displayed to visitors.
You can also hide the site message and just diplay a login box
The following will be displayed to all website visitors and search engines until you bring the website back online.