Today at Ignite 2017, we announced SharePoint hub sites, a new building block of the intranet, to bring together related sites to roll up news and activity, to simplify search, and to create cohesion...
Updated May 30, 2018
Version 6.0
Blog Post
Hi Mark Moore,
What's all the hub hub, Bub? Maybe should've copyrighted, and I say great minds SharePoint alike! The details will come certainly as we release the capability and you can devil through them on Support.com - though best expericen will be to fire one up, join a few sites and put it in your toolkit of useful tools I'm certain you'll use :-).
And you are correct, a team site or communication site can be joined to only one hub site, for the reason you suggest - it'll inherit the nav, theme, search scope and contribute back up the chain with news and activity rollup. That being said, the nav element does not require to only be populated with joined sites. You can have 100s of joined sites, of which only a handful may be showing for your desired outcome. And similarly, you can have nav elements at the hub site level that link to whatever you want them to (unjoined sites, documents, external sites/videos, etc.); aka, reference what you need. And a joined site can be joined and un'joined in seconds.
Thx for the eyeballs and healthy discussion,
Mark