Are you talking about publishing your original content on other sites?

Medium is the best in my opinion. But I would still update the content somewhat

-Medium is powerful and not so strict. You will get also a strong backlink, the possibility of traffic and can build followers. Subscribe for their newsletter to learn a lot.
-Other sites: Hubpages, Slideshare, Issuu, Buzzfeed, Alltop
-Don't just republish your article but repurpose it and add your link.
-Read their rules before publishing

Medium should be your first priority.
Other sites are:
1. Slideshare
2. Issuu
3. Buzzfeed
4. Alltop
5. Hubpages

Medium is a unique blogging platform because it does not focus on statistics and data. Instead, it encourages users to tell stories that people will read. If your post communicates something useful and different to Medium readers, then consider republishing your content on the site.

How to republish existing content the right way - https://www.godaddy.com/garage/not-q...ent-right-way/

Content and the intention it needs to fulfill. Any kinds of gaps seen and filled can help to take over the ranking position.