For me, it has started during the crisis of 2008.
Because I had time on my hand, I would go on the oracle forums trying to learn and to answer questions at the same time.
Because I was tired to answer always the same questions by copy and paste, I started to post them online.
As of today, the blog has more than 10000 articles and has between 50k and 10k users a week depending on Google algo.
Found the audience that you want to be part of be useful, add post where they are.