Tribalism

You could frame sign-up as an 'adventure', with insider-style inputs like typing 'Y' or 'N', so a niche audience feels part of a tribe that gets it.

Example from

GitHub

Try turning a dead end, e.g., a 404 page, into an interactive quiz built from your own content, so a niche audience feels spoken to as part of the tribe.

Example from

Mobbin

When someone joins a group, you could show how many people like them are already in it, reinforcing the feeling that they've found their tribe.

Example from

Discord

On a family plan, you could experiment with showing every member's avatar together in a banner, so the group sees itself as a small tribe.

Example from

Duolingo

After users photograph their bookshelf during onboarding, you could recommend communities based on their reading list, connecting them with a like-minded tribe.

Example from

Tome