A website is a site on which you will display advertising via your Revive Adserver installation.

Technically, the zone invocation tags that you will generate to display banners via Revive Adserver can work anywhere, on any website, but it is good practice to use group the invocation tags for zones by a defined website. This makes it easier to manage and track where an advertiser's campaign banners will appear, and to separate out performance statistics based on the website(s) where campaigns are running.

You may only need one website configured in Revive Adserver (for your own website, or perhaps someone else's website), or you may be using Revive Adserver to manage the delivery of banners across many different websites.