What is a personal blog for?

I've been thinking these days why I've been writing this blog. What is a blog for? Am I writing for myself? Am I writing for my friends? Am I writing for everyone in the world?

People used to write diaries, and it was a very personal thing. Blog somehow does the same function as diary, people record their daily life on their blogs. However, blog is public, and people tend to invite their friends to visit their blogs.

I used to have no problem at all sharing my thoughts on the internet. I used to write everything I wanna write here and I'm prepared to let anyone know what I think and what I did. But thing has changed recently.

I have something in particular I really want to write. I really want to keep track of my feelings these days. But I cannot write it here. I cannot write anywhere on the internet. I don't even think I should buy a diary and write it down. But I really want to keep all these memories.

Is this my blog? What can't I write anything I want to? I can't tell anyone about this. Maybe I can just keep it in my mind.