Feature Request: Hide certain parts of post.

My apologies if this has been brought up before. I think it would be neat to be able to hide certain parts of a post (sentences, paragraphs) from casual visitors or authors at certain levels. I tend to ramble from thought to thought when I blog, and not all of the thoughts should be shared with the general public (ha!), so I’ve been saving those thoughts for their own posts and have used Viewlevel to hide them. I’m terribly lazy and would rather not have to do this.
Anyone seen/heard of something similar?
Tina