I think a lot of people blog believing only strangers will read what they write - treating it like talking to a therapist. There is something strangely private about opening your life to strangers.
It's unsettling being "found out" because from that point it stops feeling private. There is huge self-consciousness when writing with a particular audience in mind - especially if these people are close or known to be generally critical of you.
Unfortunately, people you know will always find you. The only control you have is whether they realise it's you when they do!
To do that, decide outright whether you are creating a personal or anonymous blog.
- If it's personal, tell everybody about it. This makes it quite openly "yours". It's also less interesting to other people (secrets are always sexy).
- If it's anonymous, tell nobody you know about it and never post anything that could connect it to you. This stands even when you're ego is crying out for recognition.
Consider it a lesson learnt alazyknitter. Whether you can make the jump from one to the other is up to you! :)
P.S. You could always get another blog ;)