I wanted to use my first Woot post to comment, NaNoWriMo is an excellent motivator for so-called writers like me who need it. I've participated in every NaNo since 2005 AND won! (though I spent four years editing the first until I liked it enough for publication, scrapped the second, skipped ahead to 2009's and finished that, and am now picking through various other projects) The key is to remember it's a tool first and foremost--participating just because everyone else is even though you don't have any ideas isn't going to do as much good, which is an unfair criticism I've heard about NaNo. If this was a unicycle-riding contest, and you don't want to ride a unicycle, of course it's probably going to seem stupid to you.
The only valid complaint I've heard is that, come December, publishers get flooded with 50,000-word "novels" that so many hopeful writers think will sell big time, but that's something that's unfortunately understated in the guidelines. The first year I participated, they emphasized that the next step was editing, to refine the rough draft created over the course of the prior month. If people miss that, it's their own ignorance, and blaming NaNo for that is like blaming cellphone makers because stupid people talk/text while driving. But, sadly, I haven't seen the "Now edit your book!" part given much attention of late, which is unfortunate because it fails to emphasize that the core of NaNo is getting the draft out--the hard part. After that's done, editing is a breeze, even if it takes me years afterwards to get around to really polish my turds.
Overall, I owe a lot to NaNo, and it really is a good feeling having even half a novel finished in a month. Last year's was awesome, because I had no idea what most of the story was about until I happened to write it. It's amazing what happens when there's a DO THIS OR ELSE sign looming overhead.
I want to add, I'm also tempted to add this post to my word count, but I don't think I'm creative enough to pull it off convincingly... XD