Hi Jose,
The 'cf' variable returns a list of packages (from the communities the user is a member of) plus '0' if the portlet is in a 'user' portal. Otherwise it lists the package_ids of the community (and subcommunities)
So I guess one can see if '0' is in the list of package_id and that would be a user portal. Seems strange that there is no function for a portlet to determine if it in a user or community portal.