The check-in happens through a Google form. The monthly check-in post has a link to the form where you will be asked to supply your username, your pledge level, and your current total for the year. After you submit your information, we record your numbers in our fantastic spreadsheet. We use this data to spot trends in word count production and keep a record of how many millions of words our members have written over the years.
We strongly recommend that you track the !monthly check-in tag on Livejournal or on Dreamwidth, follow the Check-In Calendar, or make note on your personal calendar that check-ins are always open during the first five days of every month.