Comment by abdullin
When I was starting my community, I joined other similar communities and tried to be helpful there. No ads or links, just answering questions and supporting. People that were genuinely interested to learn more about the topic - opened my profile and followed the links there.
This and interesting content was enough to grow community organically to 14k subscribers over 2 years.
Another approach to speed up the growth - organise some fun event that benefits the entire community, highlights and showcases the participants.
E.g. when I organised last Enterprise RAG challenge, we got 350 submissions from the teams around the world. Plus IBM joined as a sponsor. People were mostly participating not for the prises, but because of the approachable challenge and ability to push state of the art. Plus some were hired away because of the good leaderboard scores.
Article of the winner (just google "Ilya Rice: How I Won the Enterprise RAG Challenge") is considered by some companies as one of the best resources on building document-based AI systems. And the entire community sees it as the result of their work together - further reinforcing the spirit of the collaboration.
People tend to share and spread fruits of their labor and love.
Great answer, more people should understand there is no easy hack and overnight success is mostly preceded by years of consistent work every day.