What are the different types of user accounts in FogBugz (e.g. normal, administrator, virtual, community)? And, what are they used for?
There are four kinds of user account in FogBugz.
A normal FogBugz user. Normal users have access to cases, wikis, discussion groups and reports as determined by permissions.
An administrator has permission to do anything in FogBugz:
Administrators are notified of FogBugz errors as well as new versions available for download at the top of any page when they log in.
There is one built-in Administrator account that comes with the Licensed version of FogBugz (i.e., this paragraph does not apply to On Demand accounts). This account is free: for example, if you purchase licenses for 10 users, you can actually have 11 accounts. This account can be deleted if there is at least one other active administrator account. This account's properties (such as full name and email address) can be changed at any time. In addition, any other user can be promoted to administrator status.
Note: In addition to site-wide administrators, FogBugz also lets you designate any user as an administrator over a project. See Permissions.
A virtual user can't log on and doesn't use up a license. Its pupose is to allow assigning of cases to a group of people instead of an individual. For example, you could create an "Up For Grabs" virtual user that serves as a sort of work queue and owns a case until someone assigns it to themselves. Give it all of the email addresses (comma separated) of the users you want notified when a case is assigned to create a notification list.
Community users are free user accounts that allow you to partially open up your FogBugz install to the outside. Only wikis and discussion groups can be fully opened to community users. You can allow this type of user to submit cases on a project-by-project basis. This is not very different from submitting cases via email. They'll be able to see a list of their past cases and all email correspondence within the case. They will not be able to see internal edits or any case properties (other than open/closed) and the case title.
Community users can be added to groups, so you can restrict the visibility of a wiki or a discussion group to a subset of users.
Additionally, you can enable the Community Case List plugin, which will extend the access granted to a Community user and allow them to see a list and view all of the cases in a project which they have permissions on.
Administrators can configure users under Admin | Users. They can move a user between these four types, configure their settings and set their project, wiki and discussion group permissions (through the use of Groups).