Microsoft Monetize - Use cases for cross-device targeting and measurement
Cross-device targeting and measurement can effectively address several key goals for advertisers, including per-user frequency capping, expanding an ad's reach to users who favor different devices, and attributing conversions that take place on a different device from the initial ad view.
Frequency capping per consumer, across devices
You don't want your customers to feel pestered or fatigued by seeing the same ad everywhere they go. By enabling cross-device targeting, you can set a frequency cap for how many times a person sees an ad on their mobile device, desktop device, and tablet. For example, if you set your ad frequency to twice a day and a consumer already saw it twice on a mobile device, the ad will not appear on a tablet or desktop for that later in the day.
Extending audience reach to new devices
Your users or customers might be clustered on one type of device: for example, you might currently have primarily mobile users, but want to take advantage of higher conversion rates associated with desktop users. Cross-device targeting broadens your reach by allowing you to reach the same users on more devices. For example, if conversion rates are higher for your product line on desktop, being able to target your mobile users when they move to desktop can boost your conversion rates.
Conversion attribution
A customer sees a clothing ad on a mobile device, clicks on it, and starts browsing on a clothing website. They realize browsing for clothes on a mobile device isn't a great shopping experience, because the screen is too small to see the detail of the clothes. The customer switches over to a desktop computer with a larger screen, logs in, and then completes the purchase. Cross-device measurement allows you to track and report on that conversion.
Warning
Cross-device functionality is available to sellers when running line items that purchase inventory from the ad exchange using RTB. It's not available when sellers are running managed campaigns on their own inventory.