How do you add users in Sharepoint Online without importing from AD? I've seen a few places mention you can do it but when I create and save a user it complains it doesn't match a name.
Regularly it should be 2 different types of "users" - those coming from AD (primary) and external users - for those that do not have/require a license. For the externals you would basically send out invitations they would accept and get access to the SharePoint site.
[Update #1 ] This link actually explains the concepts http://office.microsoft.com/en-us/office365-sharepoint-online-enterprise-help/share-a-site-with-external-users-HA102476183.aspx