The HTTP Time Protocol (HTP) system is a set of utilities to set and maintain the system clock from the HTTP/1.1 (RFC 2616) "Date:" header.
The purpose of HTP is provide a simple to use system that can be used on any system that is connected to the internet and can access atleast one web page (either directly or through a proxy) to be able to maintain an accurate clock.
HTP uses basic statistical analysis to arrive at the most accurate time possible given enough servers. The more servers HTP is configured to use the more accurate the clock can be.