what is this day light saving?

Daylight saving time (DST), also known as summer time, is a conventional local time adopted by many states of the world on a seasonal basis. Most commonly DST is obtained by adjusting the official local time forward, by one hour, for the spring, summer, and early autumn periods. DST is mostly used in temperate regions, due to the considerable variation in the amount of daylight versus darkness across the seasons in those regions. Governments often promote it as an energy conservation measure, on the grounds that it allows more effective use of natural sunlight resource in summer time. Since there is less darkness in the "waking day", there is less use of electric lights. Some opponents reject this argument (see below, Criticism). Europeans commonly refer to the system as "summer time": Irish Summer Time, British Summer Time, and European Summer Time. This is reflected in the time zones' names as well, e.g., Central European Time (CET) becomes Central European Summer Time (CEST). The word "summer" in this context includes most of spring after the spring equinox and a large part of autumn. Likewise, the word "winter" here includes part of autumn and a few weeks in spring. This varies by time zone, of course, and can change over time as well. my source? http://en.wikipedia.org/wiki/Daylight_saving_time in the philippines, as far as i could remember, we implemented this once, and i wish we could implement it again because i really found it to be effective as we could maximize our time very well.