A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
I also discovered that playing the YouTube before the show/class/service/whatever plays any ads then.
Keeping the PowerPoint open seems to holds that video without ads open in cache.
This has two effects. (1).Your audience doesn't have to watch ads (but you did) and (2) it confuses any testing process as it sometimes plays ads and sometimes doesn't on the same clip.