Buddypress User Ids

Buddypress has several methods to get the user ids.  This post attempts to clarify the differences between these:

• bp_current_user_id – Exactly the same as bp_displayed_user_id.  This is possibly an old, now renamed, method.
• bp_loggedin_user_id – The buddypress logged in user id.
• bp_displayed_user_id – this will return the user id of the user that you are looking at on a page, like someone else’s user profile.
• current_user_id – This is the wordpress user id.