Well you have missed a lot :) Communities are built around a topic and you can follow those instead of having to follow all the members. There are already a lot out there. It costs 3 Steem (and probably 3 Hive) to create one. Moderators can control what appears there.

Hive is a fork of the Steem blockchain. Everyone gets an airdrop of Hive tokens equal to their Steem except for the Steemit accounts and people who supported their fake witnesses. Obviously some are cross about that, but they still have their Steem. You can log into Hive on either Hive.blog or PeakD (clone of Steempeak). Just log in with your user name and usual Steem keys. There is a Hive Keychain extension to make life easier. Some dapps are moving to Hive, but others are sticking with Steem. It's a shame to see this, but Justin Sun has been spoiling Steem since he bought Steemit. I have to hope this will not happen again.

Hope to see you on Hive soon.