Every active player or player who has not played in the last year or so would get sent a communicate like this.
The idea behind posting such a mini mag is more about generating business for, in this case PKR. It's a marketing ploy that is common and effective.
You get a freebee read on all things PKR Poker, at the same time it's real intention is it gets people who maybe have not played for a while to reload and get involved again. It will probably have info suggesting people to recommend the site to others for a bonus to generate more business and the costs of sending it to 2million people would probably be offset by some advertising from outside businesses within it's pages, as there are plenty of businesses that would pay towards being advertised in a mag going out to 2million people.
Also as MJRACING say's, it will be read just for the fact its a hardcopy rather than an email, as emails are not guaranteed to reach recipients do to spam filters etc etc and 90% of the time people only look at the first few lines of an email and if it dont interest them they'll delete.