- large academic population and high general education
- a tradition of collecting banned and bootlegged content, particularly Western (samizdat, magnitizdat)
- lack of resources to get things legally (e.g. university subscriptions)
- a culture of hacking and tinkering (the best known book scanning middleware, like ScanTailor and ScanKromsator and various djvu tools, comes from Russian hobbyist programmers).
Also applies to adjacent countries like Ukraine.