By 2018, researchers forecast that advertisers will spend $40 billion on mobile devices, which is a 300% increase from current spending. The increased spending in revenue is attributed to Facebook and Google advertising networks. Facebook increased to 41 percent of their advertising revenue from mobile advertisements over the last 12 months ending in July 2013. According to The Search Agency, Google has around 30 percent of their advertising revenue coming from mobile devices.

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Mobile advertising to grow 300%, hit $40 billion by 2018 – VentureBeat