Steam has been banned in China since forever-ago, due to strict laws in that country regarding the sale of video games. Some Chinese gamers have found ways and means around this ban, but officially, Steam has been persona-non-grata in China, that is until now.
China now has it's own, unique version of Steam that is exclusive to those in mainland China, and as you'd expect, it's been heavily cut down compared to the mainstream version. Indeed, as of today, it only has 53 games, all of which have been approved and licensed by the Chinese government, and the client has now interactive features such as comments, message boards and other community content.
Games in China are subjected to a huge number of requirements before they'll be licensed by the government for sale, and as such, there are just 53 games available, the majority of which may be alien to western audiences. That's more than 21,000 games missing from the Chinese version of Steam, so it's hard to see players already using the workaround switching to this version, even with the promise of localised servers for games like CS:GO.
Steam's community forums, comments, and other features such as Workshop are also entirely stripped out of this version. Reviews are still intact, which interestingly shows content from the main version, and is, therefore, an interesting vector for outside communication, something that China actively tries to discourage.
Suffice to say, I don't see this version of Steam growing very quickly, either. Studios who want to publish games on this version of Steam must obtain a license from the Chinese government, something that can end up taking years, making the Chinese market all but inaccessible to indies and even a lot of AA studios. It's still an interesting step, though, and something we'll be sure to keep an eye on.