They don't track digital, but physical sales. At least when it comes to Japan.

The problem with mediatraffic is that, for most Western music, it counts both physical and digital sales, but that for Japanese sales it counts just physical sales. ALSO, for Western music it counts global sales, whereas for Japanese music they ONLY count the sales in Japan.

I think it's really unfair and doesn't really show the size of the Japanese market.

exactly.. they used to have special charts to seperate them, i believe; but now the charts make no sense at all!