IIRC, for the first few years, Facebook stored all event times in "local time", but with the Pacific time zone. So if your event was in 3 PM Eastern Time, it w

IIRC, for the first few years, Facebook stored all event times in "local time", but with the Pacific time zone. So if your event was in 3 PM Eastern Time, it would be written to the database as 3 PM Pacific Time. Did it result in bugs? Yeah, sure. Should it have been fixed to use UTC? Of course. But it wasn't the end of the world -- people lived with it for years and it worked well enough. (Engineers grumbled about the code, of course.)