Here is a screenshot of the site stats for this site:
If there are only 1330 users, then how on earth can 1698 of them visit the site everyday?
Is this a bug?
People do not have to log in to the site (i.e. to become users) to view the site. Visitors per day probably uses various means to identify distinct visitors - ip addresses, user agents, maybe cookies (I don't know the details of exactly what they use).