This often refers to a peer-to-peer networking platform that may take many shapes and often includes entities that aren’t necessarily human but are (supposed to be) represented by a human person as a representative, owner or officer of that entity. Generally it’s egalitarian and global community driven concept that allows people with different shared ideas or interests to communicate, learn and develop.
Some members may have a position of authority within an online community or by online members who are tied together by a real or traditional authority, such as a state or state body.
Generally people form communities (actively or by association) based on nationality or identity, views on humour, technological, economic, political, religious or entertainment, global issues or just human interaction with like minded people.
Any wide gathering of people whereby such interaction takes place usually attracts a commercial interest – and when welcomed it’s highly successful and when not, it’s often seen as spam or self promotion with a slightly negative context.
Brands with a strong or real and often off-line identity find a natural place where people can “go directly” to them or new brands that answer the needs of a community can find a ready and waiting marketplace that will accept and promote them.