They'll offer ideas, perspective, and help for tasks that you may be unsure of handling yourself. If handled carefully, they can help you when you need it most. Just don't depend on them for the long haul. They never stay long. A ringer may show up on a list and post wildly for a few days or weeks, but then leave just as suddenly as they came.
Ringers tend to draw fans and spark debate.
They are true people magnets. Members check in specifically to see what this person has to say. Ringers will also bring their fans with them to different communities that they join. Ringers tend to be passionate, well-versed in the rules of debate, and very savvy regarding online protocol. They sometimes build lists or communities and hand them off to other members.