Mobile Ad Movement: IronSource Buys Tapjoy and inMobi Buys Appsumer

If you think about it more than one should, mobile app advertising is also a type of retail network. Which brings us to a pair of acquisitions: App business platform IronSource is buying mobile app monetization platform Tapjoy for $400 million, and mobile marketing platform InMobi is buying app analytics vendor Appsumer. You may recall it was just last week that AppLovin bought MoPub (something we reported backwards, it pains me to admit).