It seems the term “community of practice” is getting thrown around more and more as a solution to everything.
Jon Harman from Syngenta has a great quote “Communities of Practically Everything.” And this really explains it.
But the question is why do some communities succeed where others fail?
If you take the Knowledge Management way of looking at things e.g. People, Process, Technology, this might help explain it.
The main problem is that when a Community of Practice is set up it’s normally done in the reverse order.
Technology, Process, People.
We already have the technology with the Communities of Practice for Public Service.
We already have the process, with the Help function and the Facilitators Community
But we lack in the People side. It’s not just about attracting numbers of people to join the community, it’s about encouraging interaction and making them want to come back for more.
And this is all about good facilitation.
So if the Batteries are Not included. What battery would describe the Facilitation Team in your Community?
Home brand –Lot of effort at the start to bring the community together but fades away quickly after
Alkaline – Able to bring the community together, but just as its starting to go somewhere the energy runs out.
Energiser – Consistent power over a prolonged period of time. Encourages the group dynamics, interactions and progress with objectives of the community. Also plans to replace the batteries when the power is starting to wain.
Stop, Collaborate and Listen 
To continue with the metaphor, it helps if the community has low power consumption and doesn’t waste energy! That could mean a technology strategy (avoid expensive tools you don’t need) or a facilitation strategy (avoid conversations and facilitation efforts that are irrelevant to the topic, make sure that the community actually energizes the facilitators).
I totally agree John. You need to make sure the power comsumption is balanced.
If you are putting to lots of effort in with no return. Maybe you need to look into more details why the communitiy exists, and was there a clear purpose.
Also building on the battery metaphor maybe you also may need rechargable batteries. So the facilitation and the community can be refreshed.