Check out this project, https://peepeth.com, it was launched about 4 years ago and functions to this day, (a social network similar to Twitter but based on the blockchain). Advertising in all its forms is completely absent. In addition, according to Peepeth, their back-end is open, they have no control over your account or content (although I would not say so given their claims that non-compliant messages are deleted by default). To be honest, personally, I do not see any particular advantages over the same twitter, but if you are interested, you can read more about peepeth here.