WordPress.org

How can I tell if it's working?

1. Write a new post and add this tag: [t:video type="youtube" id="vjYMIGUr84o"]
2. Look at the post online, it has to show a video (if not removed from YouTube)

Why a "qtm" directory has appeared in "wp-content"

Some tags collect information and the qtm directory is used to store them by some functions of the plugin. I prefere to not store "tags generated content" in the plugin directory (rule of thumb: keep code and data separated.. :-)