Hivemark от Hive Team

User community and rank details from Hive.one inside Twitter app
Hive.one extension helps you identify notable profiles on Twitter and know who you interact with.

When you see the hive mark next to a user's name, you can hover over it to see the user's communities and ranks within those communities. Higher ranks indicate a more prominent profile.

You can also click on a user's rank or community to see more information about them on hive.one.