What is the difference between a registered user and a concurrent user?
The RDA Toolkit allows an unlimited number of registered users. A registered user is anyone who creates an RDA Profile account. Profile accounts can be created by anyone who at one time or another has access to the site. Profiles are used to keep track of the ownership of personalization functions (saved searches, bookmarks, workflows, etc.) Profile logins are not related in any way to granting access to the site. You must have access to the site via one of the authentication methods described above before you can log in to a Profile.