They were called diaries, but back in the day they were kept private. I suppose that the editorial section of the newspaper were similar in a sense to a blog. An editorial was an opinion piece, could be written by the newspaper staff, some papers had editorial staff, or written by the readers.
Nothing. They didn't have that word. If you mean what things in the past were similar to blogs today, there were newspaper and magazine columns, clubs that met and talked, calling somebody and talking...it's common sense, these things are still around. Not like world was so different in past.
back in the day, blogs were considered a cry for attention, since you are putting all your personal information out in the open, waiting for someone to steal it. This stereotype was broken when one brave man defied the logics of the old world and move technology to a worse turn, for you see, since we have invested so much into social media, we have no time or money to invest in actual technology like space and computer languages. As for theman who defied logics and move technology forward? he went on to be the most famous man ever. His name? Albert Einstein.