Valve have long since wanted Steam to be a service that they are as hands-off as possible with regards to interference, preferring instead to add tools that allow users to control what content gets promoted and what doesn't. User reviews are a key part of this and today they got a little more useful.
With the recent proliferation of Early Access games, an awful lot of reviews are now being made for games while they are in an unfinished state, and unless you know the dates of when a game went from Early Access to Published there was no way to tell... until now. If a review is made on a game that is in the Early Access program, the review will now have a little tag that says 'Early Access Review' prominently stamped between the 'Recommended/Time Played' header and the actual text of the review itself. It's quite a useful way of knowing if a bug that a comment mentions might be due to poor coding or just that the game's developers haven't gotten around to patching it out yet.
However as of right now, the 'Early Access Review' label appears only on the reviews on games which are currently still in Early Access, and not on those games which have already left Early Access and been fully Published. Maybe Valve will go back and add the labels later, and certainly it would be a useful thing to do mainly for the reason mentioned above. For now though, it seems that Valve are on the right track with adding useful features that users can make use of to judge for themselves a game's quality.