The idea is to see how fast a spam robot will find this page, with the "test" email address shown below. This is the ONLY place this email address appears anywhere.
When spammers send out their messages, they usually do so from a throw-away dial-up account. This way, there's no trace of the actual sender.
But, when spammers use a program to scour the internet looking for web pages that contain email addresses, they like to use a high-speed connection, which is much easier to trace back to a person and hold them responsible.