Looking at the page of Business 2.0 magazine it seems they offer subscriptions in US only (no link to them provided on purpose). I tried to search everywhere on their page, but everywhere you click you will find only a US price and US subscription number. Or to be true, they mention also a Canadian price, but do not even have a form for the Canadians to subscribe.
Too bad, they lost one more customer. I suggest everyone to subscribe to Red Herring instead, they know, how to serve their international customers well.
edited: I do appreciate Business 2.0 Editor Josh Quittner posting an answer in my comments just hours after my posting. Thanks. Still the reasoning does not sound clear to me. I subscribe to many US magazines, many of them much smaller, many somewhat larger in circulation compared to B20. None of them are oriented at international audiences per se or have official circulation partners abroad, still they are all happy to accept international orders. B20 for me is the first case of a magazine not welcoming international orders. If I remember correctly, I also used to subscribe to B20 years ago, although the magazine was much different then and the Internet boom advertisers probably helped in keeping the worldwide subscriptions possible. Still I wish them good luck in their writing, which is great.