Im with ya mate, these guys have no gaul when they call up, I had some guy call up from India saying he was an autherised Telstra representative.

I called his bluff and just started abusing him, my question is why dont these fucker give me their number when I ask....

As mentioned above the best is to get a silent number, as these marketing companies either purchase the numbers from out government or just cold call from phone books.

To answer your question if you add your number to that government site it will remove your number from the lists they sell, but unfortunately you will still be listed in the phone book, so it doesnt mean much