Why not join them? Have you thought about just transitioning to running a facebook group instead? The tools don't matter as much as the community, so if the community has moved, head their way!
As far as social media goes, I disagree with CallieJo, social networks enhance a healthy community, not detract from it. How you use social media is the key, though. I use it to find leaders in my industry and invite them to join and share with my community. Reaching out to the leaders / movers & shakers of the niche subject of your community is some of the best use of your time you can spend on social media. Cultivating and maintaining relationships takes time, effort, passion, tact, and commitment. Social media is not to be spit upon, or rejected, it's a tool to be used, as long as you use it well. Wield it like a scalpel, cutting deep into the heart of your topic, finding the valuable people, and bring them to light. (hint, everyone likes to be recognized for their knowledge and experiences, so use that desire to get quality content for your community, where ever it ends up.