I am building a conference/tradeshow application where a user can assume multiple roles within the application and within a particular conference. For example a user can be an attendee, and have access to the conferences for collaboration with other attendees. The same user can be a member of an organizer account (even multiple accounts) and be able to manage the conferences the organizer produces. And at last, the same user can be a member of exhibitor account and have access to the conferences exhibitor exhibits at and manage promotional materials etc.
What are the visual/interactions patterns to allow users play all three roles and make it painfully clear what "role" they are in? What is the best way to allow for "switching" the roles?
I have been looking at Facebook and Google+ pages, and how a user can select from a top right menu "User Facebook as: BrandA" and assume that brand's identity. Seems like they are training a lot of users on the concept. Are the competing UI models for switching roles?