There are probably many different websites running off of the 184.108.40.206 IP address. It is quite common to have all the websites which are hosted by the same physical server use the same IP address. Because of this if you browse directly to the IP address the web server doesn’t know which web page to display so it displays the default website which is setup on the server which is usually the placeholder page.
What you describe is a standard method of hosting multiple websites on one IP address. The technical term is “host header names”. So, when the webserver receives http traffic to a specific IP address, the traffic wil be directed to the appropriate website using the http host header name. See this <a href=”http://www.lmgtfy.com/?q=host+header”>Google search for more details on host header names</a>.