The common belief is you can grow a community by improving the community experience.
For example, you might add new features, improve the experience, make members feel better connected etc.
Improving the community experience does help (it can reduce churn), but it doesn’t drive more people to visit the community in the first place. Long-term growth and sustainability in a community requires you to find eternal sources of new members.
That eternal part matters. A big promotional push can be great for getting a community going, but it’s not an eternal source of new members, i.e. there are only so many times you can send a mass email to your audience to persuade them to join.
To make a community thrive, you have relatively few sources of eternal community growth. These are (by order of importance):
1) Search traffic. For most communities, search is by far the biggest source of growth. However, it comes with risks. Sudden changes to the Google algorithm or Google keeping more traffic for itself is going to make this harder. If you’re a private community, you’ve lost 80%+ of potential visitors before you begin.
2) Customer/topic journey. This is when the community is naturally integrated with the customer or topic journey. As part of being a customer or becoming engaged with your organisation (or the topic) people are naturally introduced to the community. How and where the community is featured on the homepage/product/support really matters here.
3) Platform recommendations/referrals. This is when a major technology platform naturally recommends or drives traffic to your community from others (most common in Facebook Groups, LinkedIn, StackOverflow, Reddit etc…).
4) Links and partnerships. Getting links and referrals from major websites/publications can be a huge win. Community.co built an entire business doing this. If you reach out to others in your sector and persuade them to drive people to your community, that can be a sustainable source of new members.
5) Staff/member advocacy. By far the most underutilized asset is advocacy from existing staff and community members. If members and staff share posts on their social media profiles, you can attract a large number of members quite easily.
The best way to grow a community is to build the relationships, processes, and incentives to make each of the channels which are relevant to you work as best as they can.
Sure, other things can help, but these are the big wins.