From the link:
is seems very likely that Russian will stay at rank #2 for a while. Chinese would of course be the logical candidate to move up that far, but we don't see that yet in the statistics.
I was surprised that Chinese was slightly ahead of Japanese. I know that China has a much larger population, but I would assume that a far larger percentage of Japan's population has Internet access compared with China.

I wonder if technical issues related to the encoding of Chinese and Japanese иероглифы (анг. "characters") is part of the reason? According to wikipedia, Japan has been more resistant than China to adopting the Unicode standard as a replacement for older formats. So if most Chinese-language websites are Unicode-compliant, but many Japanese sites are not, that could partly explain why Japanese is behind Chinese in web statistics.

Another possible reason: As far as I know, in countries like the US and Canada, Chinese-speaking immigrants significantly outnumber Japanese-speaking immigrants. So the presence of bilingual Anglo-Chinese communities in North America (and the UK, Australia, NZ) would tend to increase the number of Chinese-language sites on the web.

P.S. Also interesting that Hindi/Urdu and related languages were not represented, despite India's huge population. I can only assume that Indians with Internet access often prefer to use English.