Earlier today, a member of SteamDB noticed that Valve mistakenly posted what should have been a private recap of the Steam Winter Sale to the general public. Below is a pasting of that recap. It even includes a "tl;dr" at the very top for those with the shortest of attention spans.
In short: More customers bought more games across more of the Steam catalog.

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More products viewed
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Not just views, but action
One of our concerns going into the Winter Sale was that extrinsically motivating customers with a trading card might encourage people to just click through their Discovery Queue and not actually pay attention to the games being presented. It turned out that customers found a lot of value in using the Discovery Queue, resulting in a huge up-tick in sales and wishlist additions. Looking back over wishlist data, we typically see only a slight increase in the rate of customers adding items to their wishlist during sales versus during non-sale time periods. However, this year we saw a 197% increase in the rate of wishlist additions during the sale. Some of these additions were then subsequently purchased during the sale while others remain on customer wishlists as indications of future interest in those games.

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Revenue impacts

It seems as though from this brief behind the scenes look, that the new format for Steam holiday sales is working out really well for getting more games and more Steam pages viewed by more customers. An 3x increase in the number of product page views is incredible.