A website is a sanctioned space on the Internet where the various denizens gather for one reason or another. Many times, it is simply to hang out and talk about various topics, in one format or another, such is the aimless days of the Internet; Others are concentrated more on some task or topic.
They usually come into being when a group of denizens feel the need for such a site and gather in one place, or a single reasonably powerful one creates one by themselves or with help from nearby websites. It is rumored that each site also gets its own eldritch abomination that gives it power and physical form, but the ramblings of the insane and degenerate are hardly to be trusted.
Sites grant some of its power to frequent and trusted residents. Some of the more powerful abilities draw on a site's power, especially those of an admin or hacker, though the latter steals the power by hook or crook.