The Internet Society are hot on this and their new website follows the POSSE principle – Publish on your Own Site, Syndicate Elsewhere. IndieWeb has more on this at https://indieweb.org/POSSE
Essentially, you acquire a home on the web, maybe your own server, a VPS, or shared hosting via wordpress.com or many others. The key thing is it is yours. Better still you purchase your own domain name and point it to your ‘home’.
At this stage it is little more than, for example a personal blog. But when it becomes the only place you publish content and when you syndicate that content out to other sites then it becomes your single source of truth. And you always have the original.
So, you publish a post and link it out to your social media channels. I can see this also helping with your Google rankings due to the backlinks. But it also means you do not need to worry about social media platform X being switched off because you don’t actually have any content to retrieve before it goes.
It’s more complex than I set out above – see the IndieWeb pages. But the Internet Society are making use of this method now, see https://www.internetsociety.org/blog/2018/03/building-new-website-posse-sharing-facebook-twitter-linkedin-google/
To me, this is has come full circle. When I started publishing on the web back in early 1993 if one wanted to publish something one found some Internet connected computer somewhere and put a web server on it. There were many such islands back then, some large, some small. Discovery was either by word of mouth or by fledgling search engines. Now with social media and the ease with which one can publish material and have it all searchable, keeping control of, and ownership of your own content is crucial.