IPhone 4S, question about data usage?

[861]

Ok so I rarely use my phone when I'm away from wifi. I practically never do. I've made it a habit to log out of Facebook every time I leave an area with wifi because someone had told me that staying logged in to Facebook without wifi uses data. I live in a city with 3G. But it pops up 4G by my AT&T bars. So I'm wondering if I stay logged in to twitter and Instagram if it will do the same thing when I'm not around wifi. So like if I'm away from my house and it says 4G and I'm on the home screen not using twitter or Instagram, I wonder if that still uses data. Or do I have to log out of that every time just like I do Facebook??? And one more thing. When I am on the safari on YouTube or something around a wifi area then I close out the safari but YouTube is still up when I click on it, will that use data too? If I'm away from wifi and I'm on the home screen with YouTube in the safari, but I'm not using it. So to make a long question short, does my phone use up data when I don't long out of twitter, Instagram, and Facebook? And does it use data when I have something open in safari but I'm not using it??? Thanks (:
P.S. I just got this I'm a little confused. S:

[Frost]

Well here in South Jersey, my iPhone 5 says 4G, but we do not have any 4G towers. I'm actually using 3G even though it says 4G. Also, if you have a data plan, you should use it. For me, I get 3000 MB a month. You only have to pay a base fee and they will only charge you extra if you go overboard. Also, you don't have to log out of Facebook like a paranoid idiot. As long as there's not a "loading circle" next to you 3G/4G, you are not using data. To be safe, double click you home button and delete Facebook from you app history. Instagram, twitter, safari, YouTube...etc they all take up data. Just make sure you don't go overboard and you will be fine. To check your data and rates go to Settings > Phone > AT&T services > View my data and msg.

[michael kelly]

No worry about the confusion. I actually worked on the I-phone design team and would me more than happy to assist you. Data usage can be tricky with smart-phones because they often recognize your browsing patterns and therefore store visited sites in the phone's memory. This is why you can start to type an address like "facebook" and it will instantly bring up the entire facebook address allowing you to simply select it on the touchscreen as opposed to typing out the entire address. This sort of memory does constitute data usage, and therefore it is imperative to delete browsing histories, like if you were surfing inappropriate sites and did not want your wife to find out. With social media sites like facebook, instagram, etc., the data usage is actually more because they are each connected to multiple servers, not unlike certain inappropriate sites you may or may not be browsing. Therefore, it is important to close out these sites when they are not in use, and then delete them from your browsing history, along with any inappropriate sites you may be accessing. I do hope this is helpful, and tahnks for purchasing the new IPhone 4S!