Once logged into Idealist.org, there are navigational hubs: Imagine | Post | Find | Connect | Reach Out | Donate
Imagine contains the tenets/principles already posted. It is the PR aspect of the site and encourages individuals to be a part of a Start Up meeting in order to become a truely engaged participant in the community. This of course, is Face-to-Face, yet the connections can be made anonymously.
Within Post, one may On Idealist, you can:
"List your nonprofit organization, NGO, or consultancy.
Post jobs, volunteer opportunities, internships, events, programs, resources, and campaigns.
Set up a start-up meeting."
In other words, its an organization page to move forward to your ideal.
Hmmm, this is looking less and less like a community, but it does have merit.