As I had to observe a community in an active participatory role, I chose the Elearning Heroes Discussions.
The purpose of this community is to have elearning professionals who are using Articulate products share their techniques, strategies, skills, and resources.
While I cannot guarantee this community would be relevant to everyone, especially, if you do not use any Articulate authoring tools, I can say it has helped me tremendously with tangible resources that I can apply to my projects immediately.
So, I guess my message is try to find a community that will help you with resources and skills you can apply to your workplace. These communities usually focus on a very specific set of skills, but they will offer opportunities for you to have a more active participation role and even showcase your work and get feedback from colleagues.
Whether you work with SoftChalk or Adobe authoring tools, try to find a community that will help you enhance your technical skills and make that or those authoring tools you and your company have investing in amazing power tools.