What is Data Allowance (Verizon)?

I have an iPhone with unlimited texting and the cheapest data plan.
What is data allowance? I keep on getting text alerts telling me that I've used 50%, 75%, 90% of the data in the pats two days.
What is it? What am I doing on my phone that is making this dumber go up? Is it Wi-Fi/ 3G usage?
Can someone tell me so I don't get charged for going over.

If I update my iPhone 4 will it erase everything?

It keeps asking me to update it to iOS 6.1.3, but I would download it on my phone. Would it still erase everything? I've never put my iPhone on the computer before. Is that bad? I do the iTunes and everything on my phone.o: if I downloaded that would it erase everything?

When I text other iPhones why is it sending as a text message?

I have an iPhone 4 I was on AT&T and I just switched to straight talk. In my setting I have all the iMessage and everything turned on. Sometimes it will work whenever I text another iPhone but most of the time it won't. I have tried turning the phone off and back on. It's really irritating. If someone could help me that would be great.

IPhone 5 power button problem?

Lately the right side of my power button has become unresponsive whenever I push it down, but the left side works perfectly fine. What should I do about this problem?

What does this Korean word mean?

I was talking to my friend on message and he said '옛날꺼? ' What does it mean? I broke my phone and he asked what phone and I told him iPhone, then he asked this. Please help, I'm still texting him and I don't want to leave him waiting, thanks^^

IPhone Message photos won't load?

Whenever one of my friends sends me a photo in messages, I have to save it to look at it. It worked before, but now when I look at photos in messenger, they never stop loading. How do I fix that?

Can i have Wi-Fi on an airplane?

I was trying to make a playlist on my iphone for when i go to florida (i live in iceland) but it didn't work so i used this app and i think its connected to the internet so can i use it on an airplane?

Added (1). The apps name is music tube? Does it connect to Wi-Fi and how much does the Wi-Fi cost?

I can't send Photos on my iPhone 4?

Every time I attempt to send a picture on my iPhone 4, it will load like 3/4 of the way and say that the message can't be delivered. Is this a setting on my phone that I can change, or could it be an issue with my cellphone carrier?

Should I choose Android or iPhone?

I have an android right now but I've noticed more and more of my friends are switching to iPhones. My phone is due for an upgrade at AT&T so I could get the iPhone 4s for $100 rather than $550. Would you say this is a good switch?