VAST stands for Video Ad Serving Template: it is the technology used by a player to interact with multiple ad sources.
Any player playing an ad is based on VAST technology and is usually served as a stand-alone format.
Viralize also offers you a VAST code which can deliver preroll video content from Viralize Premium Buyers on your own proprietary video player.
To get our VAST code choose InStream format: you will have the opportunity to earn with Viralize even if you choose a different advertisement platform.
Learn more about the VAST standard on http://www.iab.net/vast.