I share content created by other people and do not exclusively self-promote.
Social media is the main marketing channel that I use for personal branding. I frequently share content written by my competitors, content created by friends and acquaintances, content that I find interesting (but written by strangers), and sometimes, content that isn’t at all interesting to myself, but that I feel may be of interest to my audience.
There are plenty of reasons why one should share work that is not their own. It’s an easy way to foster online relationships, create a valuable experience for your audience, improve your visibility (by increasing your appearance in people’s social network feeds), and create a very human-image of yourself. It’s an image of a person that is a reliable source of information and an expert in his field- he is sharing all relevant information, not just items he created. This is how one can continue to earn trust and credibility.