Harry Poter: 3 communities, 49 users.
Hary Potter: 3 communities, 52 users.
Harry Pottter: 14 users.
Harrry Potter: 1 community, 20 users.
Harry Pooter: 1 community, 9 users.
Although the community name for that last one suggests that it might be a joke. But they can't all be, right?