It has been nearly three years since Google acquired Doubleclick for $3.1bn and despite the fact that Google’s largest cash cow is still far and away AdWords, the search behemoth has quietly built up a very strong presence in the display advertising market.

If the numbers from Doubleclick’s ad exchange are any indication, that presence will only be getting stronger.

Over the weekend, Google published a report on the progress of the Doubleclick Ad Exchange, and it had some impressive figures to share.

Perhaps the most important: according to Google VP of Product Management Neal Mohan, “when publishers make ad space available in the Ad Exchange, and the Exchange
wins the auction, publishers generate, on average, 188% more revenue

compared with indirect sales to ad networks and other third-party buyers.

Obviously, that figure will interest a lot of publishers, even if it won’t solve the challenges inherent in pure-play advertising business models. The even better news for publishers, however, is that Google is adding a number of new features that could be winners.

As detailed by paidContent, one of those features is Private Ad Slots, which allow publishers to invite select advertisers to bid on exclusive inventory not available generally.

According to Google, display spending amongst its thousand largest advertisers grew 75% last year, and real-time bidding accounts for 56% of buyers’ spend.

The evolution and momentum of the display ad space is certainly a boon for publishers, but publishers also will also need tools to protect the value of their inventory and maximize revenue. That’s why features like Private Ad Slots, which help publishers retail a good level of control over their inventory, could be very important to publishers going forward.

At the end of the day, it seems pretty clear that Google’s billion-dollar bet on display advertising was a good one. The question now, of course, is whether the increasingly sophisticated technology advertisers and publishers have at their disposal for buying and selling display ad inventory will actually help advertisers buy inventory capable of delivering ROI.