I think you need to dig down further on the customer question. Are your users going to be say small community clubs with 20 members using it for chatter, or fan boards with hundreds of thousands of users, or companies using it internally.
What does the ROI look like from the user perspective, are your users going to recoup costs through sell subscriptions to member only forums, run advertising, or are they going to be funded via patronage ?
2. The average customer would be the same as that for any other hosted forum i.e. someone without the technical chops to run a forum software themselves, but having the passion to run the community.