Lots of magazine subscriptions are handed out for free to increase circulation among a target group and thus increase their advertising revenue. As a developer I get 7 monthly magazines (each with a newstand price of $4-$5) for free. Since you just bought a Mac you are probably being targeted through that. I wouldn't worry about it, but I would watch for any invoices you may get in the mail. Often there is a trial period to get you hooked and then they ask you to pay for continuing the subscription. Just check the "No, thanks" box when it comes and enjoy the mags in the meantime.