Information Geographies collection at the Oxford Internet Institute to students in two of my undergraduate classes at SUNY Korea in Songdo. (click to see a full size version of the graphic) I'm a great fan of the various graphics being produced by the Oxford Internet Institute, and indeed the problem with this map lies in part with its data source (Alexa) rather than the Oxford researchers. I'm referring, of course, to the grey shading for Korea, which indicates "no information" and which also covers the whole Korean peninsula, merging North with South Korea.
The first part of the problem, that of "no information" about Korea may be because the Oxford team did not trust the 2013 Alexa data. I just checked Alexa and found that Google.com is listed as the top site in Korea, followed by Naver.com. However, these Alexa data are highly questionable and should not be used for South Korea. Alexa's data are gathered from a panel of users that install an English language toolbar in Microsoft's Internet Explorer. Although IE is widely used here, the fact that the Alexa toolbar is only available in English, immediately makes it almost useless in Korea, where the vast majority of users prefer web browsing in Korean. For a good critique of Alexa versus other companies that provide web statistics, see this article, "Web statistics for internet market research: pick a number, any number".
In fact, Naver.com is the most widely used web site in South Korea, with about 31 million unique visitors or almost 95% of internet users (reach) during the most recent measurement period by Nielsen Korea. It was followed by daum.net with an 82% reach and google.com ranked eight with about 12 million unique visitors and a reach of 37%.
As to the second part of the problem, that of shading the entire Korean peninsula grey, it obscures the digital divide between North and South Korea, the most dramatic and poignant such divide in the entire world and a tragic vestige of the Cold War era. South Korea has the highest rate of internet penetration in the world, while North Korea ranks near the bottom among all nations of the world.