I just realize that time zone setting will affect in some facebook feature in this case for some ‘event’. As we subscribed to facebook, we didn’t set our local time zone in to our facebook account, so we are follow the ‘facebook’ timezone, I am not sure what GMT the facebook time zone is it.

This my real life example, when I am writing this post, it’s Friday December 11 2009, On facebook I have an event that has been finished yesterday (Thursday, December 10 2009 7.00 PM). On facebook notification, this event still informed today. I assume the Facebook time is still Thursday.