content: They don't know where that data goes.  I do. Android and IOS apps are designed to not run persistently (as that would kill your battery life).  Inactive apps largely sleep. Instead of having eleventy billion apps all using unlimited data all day, the OS maintains a connection that allows notifications to be pushed to your device.  That way, you can do things like:  warn you when one of your apps contains malware notify you of app updates notify you of new mail notify you of instant messages notify apps that it's time to wake up and do something incoming iMessage texts  All of this happens even if the device doesn't spy on you at all.  More importantly, your cell or wifi network is putting you behind NAT, behind a firewall, with changing IPs.  They can't just connect to your public IP address (you don't have one), so your device maintains a constant connection in order to allow traffic to be sent back.  That takes bandwidth to maintain. Without that connection, background apps become basically impossible, which breaks IM, email, and texts, on top of skype and everything else.