Traditionally video ads were served in-stream, meaning during playback of a video content. Outstream video ads are different. You notice them on many publisher sites. They are creating new revenue opportunities for publishers.
You can buy your ad inventory on the open exchange, or a private ad exchange. Most private exchanges are owned by premium publishers or vertical ad networks. It's important your know the difference.
Great description by IAB on programmatic variation and methods of buying. Here is an excerpt - "The terms "programmatic", "automation" and "RTB" evoke mean different things to different people. This paper aims to provide clarity, from the publishers' perspective, by outlining four main ways of transacting "programmatically" today. It provides a clear framework for distinguishing between them and highlights other factors commonly associated with each "programmatic"transaction.
"barbell" sales strategy, is a term coined by AOL CEO Tim Armstrong and is defined as follows: "The barbell strategy of our advertising business connects programmatic advertising on one side with deep marketing services on the other side and connects in the middle with data and analytics".