We have a client Rowperfect.co.uk which we've just moved onto a new format for community building.

We created an experts panel (rowing coaches in this case) and are promoting their services, publicizing their blog posts on the Rowperfect platform and providing them with a private Hangout space to learn more from each other.

The mutual benefit is clear
Rowperfect gains by association with famous coaches
Coaches gain by learning from each other and from the audience Rowperfect can deliver.

We have a couple more "ideas" which are better suited for a community whose membership is not yet very large - but I'll hold them back until you get in touch.