I have an iphone 5 and 2 gigs of data on my plan. I always used about a gig so I had more than enough data. The last month or so my usage is out of control and I can't figure out why. I'm 13 days into my billing cycle and I've used 1500 megs of data. The only thing I can think of is the Facebook video thing - but I would never have guessed that it could possibly eat up that much data.