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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As you already know, the format of discounts in this year’s Winter sale was a little different from past years. This year’s sale was centered around discounts that ran for the full length of the sale, rather than changing from day to day for featured titles. Our hypothesis was that this new format would be a better way to serve customers that may only be able to visit Steam once or twice during the 13-day event. We also saw this change as an opportunity to showcase a deeper variety of titles to customers each day, while having confidence that any game being highlighted would be at its lowest discount.

More products viewed
As a result of this format change, we were able to encourage customers to browse through their Discovery Queue, thereby surfacing a string of personalized recommendations including titles that aren’t otherwise highlighted on the home page. By dropping users a free Steam Trading Card for browsing through their personalized Discovery Queue (up to three times each day) many customers were exposed to 36 different product pages every day for each of the 13 days of the event.

This resulted in three times as many views of product pages as in past sales events.

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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
As the Steam catalog expands, we continue looking for new ways to help customers discover more interesting titles deeper on Steam. Major sale events provide great opportunities for us to test out new ways of organizing offers and features to serve these goals. In terms of revenue, the discount strategy and Discovery Queue usage resulted in a resounding success.

As with past years, popular hits continue to sell well during major sales events. But what about the thousands of other titles on Steam? We looked at performance of the group of games outside of the Top 500 in revenue terms. This group collected 35% of product page traffic during the sale, which is over 4x their share of traffic from the previous winter sale. And these weren’t just idle views--we also saw 45% growth in the revenue generated by this group of games as compared with the last winter sale.

The number of games on Steam continues to increase. But the Winter Sale’s visibility and revenue growth is a great indicator that customers are taking advantage of Steam features and tools to find games they want to play, and shopping beyond the front page. As always, we'll keep working on new ways to serve customers and we welcome any feedback from partners. Thanks!

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.