If members are used to using the community for one reason, it's very difficult to get them to use it for another.
Most branded communities are customer-service channels, not communities.
The problem is it's not easy to convert a customer-service channel into a community. It's hard to turn a bunch of people used to asking for help, to a bunch of people talking about the topics that interest them within your sector.
You can begin adding interest-related discussions and hope things takes off. But that's unlikely.
The better option is to create a new place. Begin again at the inception stage of the community lifecycle. Invite a few of your more active members to join. Keep it exclusive in the beginning. Initiate discussions. Invite people to participate. Respond. Build content around what's happening. Gradually open it up to others.
