Repeat after me: a discussion forum, however it's implemented, is not a community.
@liw Please elaborate. Is that because many projects host their discussion forums on a "community" sub-domain?
@zhenech A community is a group of people with something that holds them together. That something may be an online "place", but the place itself is not not the community, it's the people.
Importantly, the people should have more in common than just the place, too. A bunch of people quarrelling about everything is not a community.
See also: https://en.wikipedia.org/wiki/Community
Lars and friends