Customers who have obtained a game by redeeming a key as opposed to buying directly through Steam will no longer be able to attribute a score to their reviews.
The move is designed to quash the danger of developers artificially inflating their review scores by handing out keys to players who in turn leave a favourable rating.
Valve has revealed that some analysis of the situation has led it to conclude that at least 160 games have obtained a “substantially greater percentage of positive reviews” as a result of key redemptions. It acknowledged that sometimes there may be a legitimate reason why this is the case, but also stressed that in many cases “the abuse is clear and obvious”.
In these instances, it has gone as far as to not only remove the reviews but also cut ties with the offending developers.