You know those people who buy a hybrid car and go crazy trying to maximize their gas mileage?
That’s how I’m getting with our AT&T data use ever since Emily and I switched to the AT&T Mobile Share + “Next” plan. It has been saving us about $50 a month  but our typical usage is pretty close to our 2GB limit. (If we hit the limit we pay $15 for the next GB, we’ve never used more than 2.1GB so we don’t like this.)
So we’re paying attention to data use. I’ve a post pending on the various settings to adjust , but in the process of researching that I ran across a mystery that’s not addressed in Apple’s documentation on their bizarre  cellular settings panel or the iPhone documentation. The mystery shows up in the top rank of the almost-hidden Cellular System Services list.
There you see “Exchange Accounts” — you can’t disable cellular services for these. There’s also “iTunes Accounts” - which can use many MBs of data even when you don’t buy anything on the iTunes Store and you don’t listen to iCloud Music or Podcasts over cellular.
So what are iTunes Accounts — really?
My best guess, based on a process of elimination and occasional rumors (Google failed me on this one), is that “iTunes Accounts” is a misnomer. I think this is referring to everything in “Mail, Contacts, Calendars” that is NOT Exchange Accounts and doesn’t have an entry on the Cellular menu. On my phone that includes my iCloud Contacts, Reminders, Safari settings, Notes, Passbook, and Keychain. Like “Exchange Accounts” these can’t be set to avoid use of cellular data, you can only tweak data use in “Fetch New Data”.
So why doesn’t Apple document this? My theory is they’re too embarrassed to cop to calling this stuff “iTunes Accounts”.
I wonder if it’s renamed in iOS 8 or if these services can have cellular data use disabled.
 For many people this plan is moderately more expensive than the prior plans. We’re unusual, with our usage pattern it’s a savings even after we account for the lost subsidy and all of our future phones will be unlocked.
 Bizarre, yeah. This menu is empty on a new phone, entries appear when data is used. You tap TWICE on the reset link to reset the data records.
 I think those settings are going to keep us well below 2GB by the way.