You have exported a list of your contacts. Everything seems flawless, but under the Date created and Date changed fields, you realize that there are some past or future dates. Why is this so?
The cause of this is that the dates in the system are stored in UTC - Universal Time Coordinated. This is the primary time standard by which the world regulates clocks and time. GMT is also a term you may have heard, which is a synonym for UTC.
The main benefit of storing the time and date in UTC is that the time will always remain consistent. It will not be affected by different time zones and clock shifts.