Your servers, and likely your desktop computer, gets the time from a public NTP server. NTP servers are provided as a free public service by volunteers like us. Accurate time is important to the internet for caching and other reasons. We have had one of our servers in the pool for several years, but more servers are needed, especially in countries other than the US. It only uses about 10 kbps, so please consider joining the NTP pool to give back a little bit to the internet if you have a dedicated server.
http://news.ntppool.org/2012/06/more...rs-please.html