Usage data representing users' actions with applications, client devices such as PCs, and peripheral devices like personal media players is collected from a variety of sources and utilized by an automated user profile population service to pre-populate user profile forms with suggestions for entries that can be presented to an application user when initially registering with the application or when a user profile gets updated. The user can review the suggested pre-populated entries in the user profile form and accept those that are appropriate and desired and reject those that are not.