A VAST tag is essentially a third-party ad tag generated by an ad server, except that it’s for video ads. VAST stands for Video Ad Serving Template. It enables video players to sync with ad servers, thus as an advertiser, you can serve ads into multiple ad inventories within video ad players. Put simply, it enables your video ads to appear correctly on video players, across different publishers and ad networks. As an advertiser, you don’t have to build your own…