The NTP Pool Project

Computers are notoriously unreliable for keeping accurate time clocks. If not set up properly, a computer clock tends to drift ahead or behind the actual time, frustrating those who use their computer as a watch or personal scheduler. The technical solution to this problem is NTP (Network Time Protocol). NTP allows your computer to synchronize its clock with master servers that are themselves linked to official national time clocks. It works well as long as these chosen servers keep running.

The NTP Pool Project is a volunteer effort whose goal is to create a large distributed farm of new NTP servers across the world. Theoretically, a server pool reduces the likelihood that technical glitches in the NTP system will prevent your computer from synchronizing its clock. The risk isn't worth worrying about in practice. For added peace of mind, however, you may still like to configure your computers to use this service. You can even join the Project and learn to set up your own NTP servers.

→ More - NTP Pool Project (pool.ntp.org)