Active area is indeed the size you can draw on. That section on the Wacom site has an error. It looks like you selected medium, but it's still giving you dimensions for the small. 6 x 3.7 inches is the dimension of the active area for the intuos art/comic/photo small.
Your Wacom Graphire Bluetooth Dimensions: 11.5 x 10.5, Active area: 6 x 8 inches
Small Wacom Intuos Art/Comic/Photo (All the same tablet, different bundled stuff)
Dimensions: 8.25 x 6.7,
Active area: 6 x 3.7
Medium Wacom Intuos Art/Comic/Photo Dimensions: 10.75 x 8.75, Active area: 8.5 x 5.3
The old tablets were the Bamboo and Intuos. The former being the hobbyist tablets, and the Intuos 2, 3, 4, 5 aimed at the professional market. But they changed the name a few years back. The Bamboo became the Intuos series, and the Intuos series became the Intuos Pro series.
Now they've released a new set of tablets, but they didn't add numbers to them, so look out for anything labelled (OLD MODEL) on Amazon, unless you specifically want the previous release.
Confusing huh? :)
tl;dr The Intuos Art Medium has an active area of 8.5 x 5.3. Wacom's site is wrong.
Edit - good formatting is hard here, sorry about the mess.
Is she doing graphic design? Depending on the kind of work, a tablet could be totally useless/worse than a mouse.
As far as I've ever seen, Wacom is pretty much the industry standard, and everything else is pretty much off-brand. Never once seen a professional use anything else. Also, I think this is the current version of the Wacom you posted, although I've never heard of an "Intros Draw" before.
If she's really interested in illustration or photo editing as a career, I would suggest investing more than $100 because she'll probably want to upgrade when she starts working, but this all depends on a lot of things.
Edit: I just looked at some of the Huion's more closely, and if this is just for class and you're going for something in that range, then they're probably fine.
you think? I got this one just havent invested the time into it.
Wacom Intuous I have one of these and it's great. This is a smaller version of the one that I have, but it's a quality pen and touch to start out with.