You're by no means the first person to be confused by the manner in which iTunes (either the older version or iTunes 11) displays the data that's eating up the space on your iOS device, whether it's an iPhone, iPad or even iPod. Heck, even the most primitive iPod gets the same little graphic display when you plug it into iTunes.

But what is this yellow "other" category of data? Turns out that it's actually additional storage space needed by various apps, typically for data files. It's confusing because if you download a big game, the "app" is a certain size and that's the size displayed in iTunes related to that particular app. But what if as you use the app it creates additional data files or stores interim states in a game or additional downloaded (perhaps in app purchases) content? That's "other".

What's cool is that armed with that information you can actually dig around on your iOS device and see what's consuming the most "other" space on the device. Not within iTunes, but on the device itself.

But let's start at the beginning. Here's what the old iTunes showed for my iPad 3:

Look closely, you'll see that "other" consumes 1.26GB of space (though I have a lot free, rather unusually).

Switch to my iPad Mini and the device is a bit more full:

And yet, it might have more stuff on it, but the "other" category - shown in yellow - is just a bit under 1GB of space.

One more, my iPhone, as shown in iTunes 11:

In this case, putting the cursor over a colored segment pops up a bit more explanation of what that encompasses, as you can see. Still, 1.43GB? What the deuce??

To figure out what's taking up space, I'll switch to the phone itself, to the Settings utility. Tap on "General" to get here:

At this point, tap on "Usage" and give it a second to accumulate all the information it needs. Finally, it'll show something like this:

Let's have a look at "Sonic 4", since because the list is sorted by space used, it's the biggest app I have on my iPhone. To look closer, I simply tap on the app name:

In this case, you can see that the app itself is huge - 704MB - but the additional space used is tiny, 1.0MB or so. That's not the main culprit with the "other" space, so let's back up and look at a different app on the list, Dragonvale:

Now that's a different story. The app is super small at 33.9MB, but the game uses an additional 228MB of space. That's about 25% of the "Other" space used on the iPhone.

Since my kids are big fans of Dragonvale, I'd get into all sorts of trouble for deleting it, but you can see how to ascertain where that additional data is coming from and if it was an app that I wasn't using much at all, a single tap on "Delete App" would remove both the app and its data file.

Hope that helps explain the "other" category on your iOS device and how to manage it.