I have had androids since the OG Droid. I now have the Galaxy Nexus and for the first time EVER I have gotten a warning message about data. I'm trying to be more conscious about my usage - and read up on that Facebook post on here since I've noticed that FB is extremely data-hungry. The next thing I notice that is using the most data is the Google Play Store and a lot of it is "background" data. How can I disable these apps for running background data? I notice when I press "restrict background data" and it says that it can only be possible when you've set a mobile data limit - so do I set a mobile data limit for myself? If I'm on the "unlimited" plan what is my data limit? (I know it is not truly unlimited). And same with the gmail - its mostly background data - WHAT IS background data? Additionally, I have "Advanced task killer" on my phone and I notice there's these apps that open up that I NEVER use except for once a month or once every other month but are ALWAYS open. Why are they always open if I never open them? Is there away to make them ALWAYS stay closed UNTIL I use them? I'm betting these are killing my battery too. I have the "Advanced Task Killer" set to Auto-Kill and set to do it frequently but it sure doesn't seem to be doing much. Any help to optimize my phone would be helpful.