It's the reason my LJ entries all take place sometime past the year 2010. I set my system clock to that to avoid a virus, but when I switched back to the correct year my LJ was now convinced that if I posted in 2004 I was back dating, so rather than go back and correct my old entries I just went with it, fiding a year in the future where the days of the month and the days of the week matched the current year. Unfortunately 2012 was a leap year while 2006 was not, so I had to make another jump in years.