MSN is Microsoft's content network, stretching across weather, news, finance, sports, health, fitness, and food & drink. Originally MSN was web centered, offering all the content via MSN.com. Now, with the move from Bing apps to MSN, there is a family of beautiful MSN apps across platforms which showcases the content on any device. Microsoft's plan to monetize MSN has primarily been done with ads and now a new cross-platform in-app ad spot is being offered to third party advertisers.
Conveying a consistent brand with consistent ads is the aim of most companies, and Microsoft is trying to make the MSN apps the easiest place to do that. Since the MSN apps are available on Android (including Fire devices), iOS, Windows and Windows Phone, ads will be displayed to a massive audience across platforms. Users who use MSN apps can customize their app and those personalized changes will follow them across devices, so it only makes sense for the ads to remain consistent regardless of which device is being used.