Baidu's Baike is a truly gigantic wiki. Often whole articles from the Chinese version of Wikipedia show up there, but Baike is actually much larger.

I agree that blocking the international internet is harmful to innovation and the economy, but the question of how harmful is largely based on how large the market is. In China's case, Baidu isn't as extensive as Google, Youku doesn't have the Khan Academy or a lot of other things YouTube does, but they're still huge and it's not that bad.

China's internet isn't as rich as that of the entire world, but it's still large and vibrant. For the Russian internet it's a bit worse. If a country the size of Denmark decided to only their own versions of fb, youtube, wikipedia, etc, it would be a catastrophic loss.