Many PHP applications require to parse e-mail messages. For example bug systems and ticket systems that want to allow input by e-mail. For sending e-mail there are already decent implementations, ones that even allow sending multi-part and mixed text/html messages with attachments and so on.
He gives an example of how the component can be used to grab the mail from a remote POP3 server and display the parsed results with a few echo statements. Getting different values in the mail messages is made simple and is as easy as using structures like "$mail->to->email" or "$mail->body" to reference the content you want.