This is the most idiotic thing I have heard.
Changes To The Review Score
As a result of this, we are making some changes to how review scores are calculated. As of today, the recent and overall review scores we show at the top of a product page will no longer include reviews written by customers that activated the game through a Steam product key.
Customers that received the game from a source outside of Steam (e.g. via a giveaway site, purchased from another digital or retail store, or received for testing purposes from the developer) will still be able to write a review of the game on Steam to share their experience. These reviews will still be visible on the store page, but they will no longer contribute to the score.
This does mean that the review score category shown for about 14% of games will change; some up and some down. Most changes in the review score category are a result of games being on the edge of review score cut-offs such as 69% positive or 70% positive. A change of 1% in these cases can mean the difference between a review score category of "Mixed" and "Positive". About 200 titles that only had one or two reviews will no longer have a score at all until a review is written by a customer that purchased that item via Steam. In all of these cases, the written reviews still exist and can easily be found in the review section on that store page.
So, basically, Steam is saying if you didn't buy it directly through their store, then your copy of the game shouldn't be counted in the review/score index.
That means, that if you were to buy AotS or the Expansion directly from StarDock or GOG (or Amazon, or Gamestop, or anywhere else) and if you make a review, then, too bad for you, it won't be counted.
And this is supposed to prevent fraud? Ha!