I didn’t know about your community till I saw this post, and I’m interested. Have you considered adding a community-maintained “getting started with geocaching” doc to the sidebar? I’m not saying that’ll solve the problem immediately but I think it could help people decide to join when they’re exploring Lemmy.

Like others said, such a small percentage actuslly post. So anything that helps drive traffic up can help. From an seo perspective you’ve just got to be the most helpful resource if you want that sweet sweet traffic.