What are some of the special features of the RealServer?

With the Real Server, you are able to take advantage of "bandwidth negotiation". This feature takes into account the bandwidth of the surfer's Internet connection when clicking on the hyperlink that requests the RealMedia file. Depending on the connection, the RealServer will provide a different version of the RealMedia file that best suits the visitor's bandwidth connection.

You also need the RealServer to broadcast live on the Internet.