Acquaintances should not read the blog. Others can read if they come to know about it or come across it. But the advantage is that they would not come across in ur daily life or if they become ur friends, then it would be in the close friends circle ( somehow this theory of mine should be refined. Help needed....)
Another option you can do is to have a blog and be an unknown author. Act to be Mr. X and disclose you identity to the selected few.
I recently created a new blog (Malayalam). Before creating, I thought I'll play some Mr. Unknown - I have always wanted to be a Mr. Unknown (kind of fantasy). I even created a new blog and all setup. But finally I decided that whatever I say has to be mine and I would be proclaiming that proudly. Why should I think some person should not know that it's I who is thinking/writing? Hence I came back with my real identity - I was very uncomfortable till I came back to ME - That is my existence. So this Mr. X thing really doesn't appeal me.