Why is data showing up for "Week 53" in my stats? Aren't there only 52 weeks in the year?
There are a number of days either at the beginning or at the end of the year that are not part of the "normal" 52 weeks of the year. PHP and/or MYSQL treats weeks as being not just any 7-day period, but specific periods from Mondays to Sundays. This can leave some "stray" days if a year starts or ends in the middle of a week. For example, in 2005, the year started on a Saturday. PHP/MYSQL does not treat the two days of Saturday and Sunday as the first week of the year, rather "Week 53".
Answers to the majority of questions we receive can be found here in the knowledge base.