I actually can't answer this question.
I do it because I know strangers and friends read it. Friends can read it and sometimes we chat. But there's an allure in knowing strangers are reading these words. Hi stranger, hope you are well.
Interestingly, people seem to differ in their idea of blogs. Some maintain that it is for publicity, others for social networking, and some use it literally as a journal. But I guess in the end we're all just trying to connect with people in a different way.
I used to write random thoughts down on paper. But it seems weird to just give that piece of paper to people to read, and at the same time I felt like the paper was all lonely just sitting in my room. So then I started blogging. (I also type faster than I write so this helps since I tend to just type down whatever is going on in my mind at the present time- my hands can't keep up with my mind)
But I always need to keep in mind that because people are reading this, I have to be careful what I write down. Some things I wouldn't mind letting out, but thoughts are quite private some other times.
Time and time again, I thought it would have been nice to never have told any of my friends about this blog- and to just write to strangers each time. But there's always this gentle hope that one of your friends will see you one day and mention to something you wrote- and golly, what a nice feeling that is.