on Jami Gold site:

For the past several years, the Scrivener drafting program has been one of the sponsors for NaNoWriMo and offered deals to participants. Beyond the “try free for 30 days” version anyone can grab off their website, NaNo participants usually get 20% off and winners often get 50% off a full license.

In fact, that’s how I first started using Scrivener. The year I first participated in NaNo, they offered a special NaNo version of the software, programmed to expire after NaNo and preset with the 1667-words-a-day/50,000-words-for-the-month target. Then after I “won” NaNo, I purchased the software to keep.

So it’s not surprising that many writers use Scrivener for drafting their stories, especially if they’re participating in NaNoWriMo. The program is great for tracking daily word count and inspiring us to hit targets.