Many people spend much of their day marketing themselves through blatant self-promotional messages as if to say: "Look at me. Hire me." Much of what they share is about them and what they can do for you.
But other people spend their day making meaningful and timely intellectual contributions to their profession, ones that others find valuable and that cause them to sit up and take notice. Much of what they share is about you and your needs and they provide value for free.
With limited hours in the day do you want to spend them trying to get the world's attention for you ... or do you want to spend them doing work that gets the world's attention?
I would strongly suggest you favor the latter. The best form of self-promotion is not promoting the self, but selflessly contributing to others' success.