Yep, it's Merriam-Webster's word of the year...and I think this is the first time I have ever used it, so I guess I'm a bit out of touch with the hip, newish words floating around...
Yeah, I've seen it used, and I knew it was a joyful interjection of sorts...heck, I even knew it was a kind of l33t sp34k (a.k.a. "leet speak": thanks, Z.!)...but I had no idea is was so popular. Hmmm.
Personally, if I had to choose a word from Webster's top ten list it would have been "Pecksniffian" but hey, that's me!