It is easy to flood people with your email products - never mind that you might be breaking the law - and to claim a circulation of hundreds of thousands. But actually maintaining a healthy subscriber base of proactive and willing recipients is another thing. There are only two ways to join the DMC mailing lists. You can apply to join from the mailing list page of the website itself, or you can respond to an invitation message that David himself can initiate (all he needs is the person's email address).

So here is a 'pull' rather than a 'push' product. As for withdrawals, David tells us there have been five to date, including the computer engineer who set the thing up. How fickle is that?