It appears that Steam is asking players who have reviewed games to revise their reviews after added playtime, as reported by PCGamesN. Although not logged in the changelog, the feature was first observed by a Reddit user, and Valve UI designer Alden Kroll also confirmed it on Twitter.
Thankfully, the feature doesn't look invasive, based on the screenshot posted on Reddit. It only shows up on the game page when browsing to the game in your library. The text on the photo reads “You’ve played an additional 93 hours. Would you like to revise your review?”
This could help clean up reviews on Steam somewhat, as they’re known to include reviews from users bashing the developer or issues related to their purchase. Players who get frustrated in the early hours can also negatively affect reviews, so it makes sense to ask users to review their review after they’ve put a solid number of hours in.
Of course, Valve has been fighting this ‘irrelevant review’ battle for longer, giving users the ability to flag reviews and sort reviews based on playtime. Of course, this requires active effort, and many of us just skim the review page briefly before deciding whether or not to make a purchase. This change probably won’t improve the situation drastically, but it should help contribute to forming a nicer community.
If you don't mind the spooky world of game reviews though, consider having a look at the Steam Halloween sale.