It's not surprising that he didn't reveal the list of countries at the time, because now that the list has been revealed it's not as impressive as you might have first thought - none of the seven countries are what's known as "advanced economies" by the IMF (PDF).
The list is as follows: Argentina, India, Poland, Russia, South Africa, Ukraine and "rest of central and eastern Europe" (apparently this is one country). The stats come straight from IDC, which were the research firm behind the stats in Shaw's initial blog post, and also revealed that three of the markets (Ukraine, South Africa, and "rest of Europe") had fewer than 100,000 Windows Phone shipments each for Q4 2012.
The fact that Windows Phone has outshipped the iPhone in these markets is not surprising, as Argentina, Russia, Poland, Ukraine and "rest of central and eastern Europe" classify as emerging markets, while India and South Africa are newly industrialized. Apple only produces high-end, expensive devices while there are a range of low-end Windows Phones (such as the Lumia 620) available; people in these countries are less likely to be able to afford an iPhone, and so have a greater chance of purchasing a Windows Phone.
While it's certainly good news that Windows Phone is breaking into emerging markets, Windows Phone has had issues breaking in to the tough, and arguably more important North American market as of late. Tackling the developed markets is no doubt a priority for Microsoft at the moment, and with Nokia continuing to release new devices, progress will come.