I will be interviewing a potential PHP developer this afternoon (see top of the index page) who was born in Russia. During my WebmasterWorld travels, I found a new thread named SE popularity in Russia. The thread creator, Blackie, who claims to have "actual SE use by different people in Russia." The results he posted include:
Yandex - 49,46% Rambler - 22,27% Google - 12,38% Mail.ru - 5,12% Aport - 2,29%
I'll update this entry later after speaking with the person I am interviewing. Of course, it will be his opinion.