Valve has tweaked how the user review system works on Steam in an effort to combat review bombing, which has been an area of concern for some developers for quite some time.
Off-topic content will include obvious things such as storefront changes and exclusive publishing deals, and also complaints that are related to, but not actually about, games, including the presence of DRM and changes to EULAs.
If the review bomb is determined to be off-topic, Steam will isolate the time frame of the review bomb and remove the reviews within that window from the game's Steam Review Score. Valve is working on a few more changes to user reviews as well, but they'll be shipped out at a later date. Valve defines an off-topic review bomb as "one where the focus of those reviews is on a topic that we consider unrelated to the likelihood that future purchasers will be happy if they buy the game, and hence not something that should be added to the Review Score".
A "review bomb" is a sudden influx of a large number of negative user reviews of a game, usually regardless of its actual quality, meant to discredit or punish its developer or publisher.
"We believe that players who do care about topics like DRM are often willing to dig a little deeper into games before purchasing - which is why we still keep all the reviews within the review bombs". "The reviews within that time period will then be removed from the Review Score calculation".
Steam will now remove the effect of "off-topic review bombs" on the user score displayed at the top of a game's store page, according to the announcement. As the review bomb filtering system just excludes a certain cluster of reviews from counting towards the overall score, this will also filter out any legitimate reviews during that period, but at least it will be across a period decided by real flesh-and-blood humans. To be clear, this will only impact what you see: You can not influence whether off-topic reviews are included in review scores for other people. Because review bombs tend to be "temporary distortions", all reviews will be caught in the net.
Review bombing has been a serious issue for devs, with Devotion being the latest game to be hit. One such flaw is that any genuine reviews posted during what Valve deems to be a "review bomb" will be filtered out alongside the off-topic posts.
Steam users can still see raw review scores, even those that are considered off-topic if they choose. And, again, people will apparently still be able to look at reviews that have been removed.