It's unclear, actually. Having just trawled their FAQ it is not exactly stated. They claim a % of each post (rightly so) and I had understood as long as you keep posting, content stays up.

I KNOW dtube does not keep content, so don't use. And it's cumbersome. @3speak allows comment from non steem people, which I like.

So are you saying @travelfeed only supports posts which use youtube video???