I don't think we can avoid advertising, but it will be different on steem. I'm guessing people or businesses will pay high profile users to mention them in videos and place ads on their posts. The payment might be in steem, but I don't think anyone will be able to get away from this, unless people decide they don't want to advertise someone else's product. But I really don't think it will be a bad thing, if you don't like the ads just stop following the person.

One thing to watch out for will be using voting bots. If enough corporations create accounts here they can take up the entire trending page with crap ads. Then we can flag them all haha. It could get interesting, but I don't think we can censor unless we do it as a group.