If I stay logged onto Facebook on my phone but don't use it, will it use my 3G?

[Poppy]

[Finesse]

Only if you're on that app. Your phone knows when the app or Internet is in use or not BUT It will never hurt to make sure and check with your service provider !

[Luke]

Very very slightly, I get 1gb a month and never come close to using it all and I leave mine logged in 24/7

[Daniel]

Yes it will Still Use you 3G Connection Regardless if your Using it Or Not When your Not Using it Tho its Not That High

[WALL•E]

Yes.. but very very less, if you lock off your phone it'll automatically disconnect the mobile data, you need not to worry about that but it will drain your battery