Which is good for me because I haaaaate complicated graphs.
You can also "friend" your friends on your FitBit profile and compete with them. Now I see why my sister got me one. (I've never known anyone more competitive than her.)
I wear my FitBit when I remember - which is most days. There have been days where I know I won't be moving much (say, I'm driving all day) and I choose not to wear it because the numbers will just depress me, but on normal days when I do wear it, it's a motivator. My goal is 10,000 steps a day; I never get that without exercising and in the winter months, it's hard to get outside, so it's been kind of fun to walk around the house and home gym like a crazy woman and watch my numbers go up. (Okay, maybe some of my sister's competitiveness has rubbed off on me...)
And here's a testament to its durability: My husband wore his when he was snowblowing our driveway. Somehow it came off of his pants (I'm not sure how this happened because mine hasn't ever come loose - he must have been snowblowing pretty aggressively) and it was missing, in the snow, for a good five days. We looked and looked and finally, Allen took a rake to the snow and found it. With a quick charge it was back and running again.
Here's a great Scientific American blog post on the 'bit.