Wifi Sleep

If you're noticing your Wi-Fi connection turning off when you put your phone on standby, your Wi-Fi is likely set to turn off with your screen. This saves your battery but costs you data use; any applications like Gmail, Facebook, news, weather and others that sync in the background will be forced on to the mobile data network. Likewise, if you're downloading a file or an application and you turn your screen off, the download will continue on the mobile network @ butterscotch.com: http://bit.ly/tQKh4e