Mousethyme, one benefit to using the NaNo counter on the actual NaNo site might be that you get rewards for "winning" NaNo. Now, do they check to see if your counter is at 50k? No idea. But you do get a certificate, so there is proof that you at least lied about your word count hitting 50k. I feel like there's some special link or something you get, but I can't recall for sure. I do know that winning NaNo has been a goal for the last few years so that I could get some of the goodies they are offering. On the main NaNo page, check out the Offers link, I think it's called. Also, check out the forums. There's lots of goodies there!