Valve have announced that as of Tuesday, 25 September 2018, the company's team will start moderating comments on and reviewing discussion posts on Steam's game hubs, although developers can chose to opt out of this service if they wish.
The way this will work is once a community thread or post is reported, it will be queued up for Valve's moderation team to look at. If they find anything that violates Steam's community guidelines, off it goes to the trash can.
Note that this does not mean Valve and Steam will be pestering all dev or community threads or comments that they don't find fitting. "You have your own voice and your own style of communication with players about your game", they said and added that they'll only communicate with players when issuing warnings or bans for reported content.
If developers have their own moderator teams or just wish to protect freedom of speech in its rawest form, they can choose to opt out of this service and keep Valve's team away from their message boards. This should be as simple as accessing Steamworks settings and finding the appropriate option in the Community Tab's General panel.
Valve pointed out that while Steam's moderation team have been "reviewing and taking appropriate action on many forms of reported community content", they've done so in moderation, badum-tss. The company did not want to "step on the toes of game developers that want to have their own style of communication with players".
However, they've also heard pleas by many other game developers, who would rather have Steam's moderation team take on a proactive role in this, at least when it comes to reported posts. With this in mind, Valve have apparently been expanding Steam's team to accommodate for these changes.
Seeing as how anything related to censorship is a double-edged sword, I personally think it's great that Valve found a middle-ground solution. Perhaps doubly so when considering the sort of censorship pressures they've been subjected to lately but thankfully - GabeN and Co didn't buckle and go for the extreme.
You can find the official announcement here.