sns interworking

It may mean that you can upload the contents of a website on SNS, or you can log in to the website with an account on SNS.

The Hashcode site supports login through Facebook, so it is linked to Facebook, and if you look at the top right of this article, you can share the link of this article on Naver/Twitter, so it is also linked to Naver/Twitter.

However, it doesn't seem right to say that can be shared with each other. You can share the contents of Hashcode on Facebook/Naver/Twitter, but the site does not provide the function to share it with Hashcode.