It's funny, I don't really mind random people on the internet to read my personal blogs, but when people I'm close to read them, I feel kind of exposed and uncomfortable.

Most people I am close to do not read my blogs (some of them do not even have internet connection), but even if they do, I would not feel exposed, nor uncomfortable, even when they get to know that I have done some mistakes. Some of them even know my mistakes (not from my blogs, but by my honest face-to-face admitting), and they honestly express their opinions about it, and I accept it. I trust them and they trust me. Being honest with each other is giving me good feelings, like being free. And admitting my mistakes also giving the feeling as if a great weight was lifted from me.

I agree, it's good to talk about your problems. Honestly, it can even be easier with strangers.

Not necessarily. there are bad people in the world, who look for any (even for the slightest) mistake you make (or simply for any of your problems), and they either use it against you or simply attack you for it. So because of this, it requires some kind of bravery and strength to admit your mistakes (or talk about any of your problems) in public, but I still encourage people to do it.

It is better to give out than suppress in yourself.