If you have noticed that ads from Facebook (not for Facebook, from Facebook) are now showing up in apps on your phone or tablet, you’re not alone. Facebook announced the ‘Audience Network’ (FAN) in 2014, which is a way for advertisers on Facebook to extend their reach (and their ads) into non-Facebook apps, and it seems that more and more app-makers are serving up these ads in their apps in order to generate advertising revenue.