Someone on the NaNo boards pointed out the theory that apparently your wrirting takes a leap of improvement every 100k words you write. I'm not sure that is true, but I did reread my 2003 NaNo a few days ago to get some motivation and I was shocked at just how bad the grammar was. I had the later chapters beta-read, but the prologue alone had seriously wandering tenses. I can't believe I didn't manage to stick to a single tense. But at least I can see that my grasp of the English grammar has improved in the last three years.
Another interesting site that someone pointed out was the snowflake
I'm planning to meet some NaNo people from the boards on Sunday afternoon. I'm a bit nervous about that, but I did go to a few NaNoWriMo meetings in the last years and it has always been fun.