They stated that at the time they decided to remove review bombs, they defined it as “an event where players post a large number of reviews in a very compressed time frame, aimed at lowering the Review Score of a game.”, since there were no examples of one “positive review bombs”.
According to Valve, what happened to AC: Unity seems not to be a case of the review bomb as actual players increased alongside the reviews and most of the reviews looks like standard reviews of a new player, or a player that’s returning to a product they bought a while ago.
And about if it is off-topic or not, they said they’re not sure since context can change. Mentioning that if there’s a game that heavily focused on Christmas, they “suspect we’d see it have Review Score fluctuations around Christmas-time”.
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