If the State and Market are two pillars of society the third pillar is the community. Dr. Raghuram Rajan's book by the same name inspired us to bring everything we were thinking about under this umbrella term. Hope he is kind enough not to sue us.
Space-based - USA, India, China at a national level -California, Karnataka, Beijing at a state/province level all the way up to the unit levels of administration.
Skill-based - Marketing to Farming - this is the most fundamental way to look at a community.
Language-based - Tamil, Chinese, English etc
Sexuality-based - LGBTQ, Hetero, etc
Interest-based - Boardgames etc
This is not an exhaustive list. Anything that brings together people together could be considered a community
There's no point in saying caste doesn't exist / caste should die. If something exists for centuries maybe it's time to accept that they exist for a reason. In India, a caste system. varna system is based on the nature of the work you're doing. It's a fundamental way to group people so it's easy to manage. So yes, we are re-inventing the caste system.
The caste you're born into doesn't matter within the thirdpillar network. You choose a skill-based community based on your need/interest and that becomes your new caste and nothing is stopping you from being part of multiple communities.