Microsoft Invest - Impression counting

Microsoft Advertising counts an impression, and records payment to the seller, once we receive an "accept call", which notifies us that a creative was served to the web page or mobile app. Because the amount of time between when an impression is requested and when the creative is served varies by media type, we have defined appropriate look-back windows for each media type.

This flexible approach is especially important for media types like mobile video, which can pre-cache an ad long before the ad is actually served, as well as interstitial and native media types that require a longer window than standard formats.