I found it really confusing at first as well, but after using it for a while, it really does get easier. One thing I don't like for video promoting though is that people can't comment on your posts. The only way to "comment" is to reblog and add their own writing in their post.
On the other side of the story, though, I LOVE using Tumblr to find other vloggers. Since so many people are posting their videos on their blogs, it's easy to find people who are working hard to grow their audience. I just search the "vlog" tag and watch the ones that look interesting.
