Thankfully, custom Profile subtabs give those orgs an option to extend the Chatter Profile without having to completely re-engineer the entire page (which is not really feasible considering the Chatter feed and related components). What's required is some Visualforce magic to expose related information directly on the Chatter Profile page as subsequent tabs coming after "Feed" and "Overview".
To provide access to personal data without exposing that data to other users, Salesforce provides a thoughtful separation of different subtab use cases. Admins have the option of showing custom subtabs in one or more of four different contexts.
- Profile (Others): When a user looks at someone else's profile in the internal Salesforce "community"
- Profile (Self): When a user looks at his/her own profile in the internal Salesforce "community"
- Profile in Communities (Others): When a user looks at someone else's profile in a customer or partner community
- Profile in Communities (Self): When a user looks at his/her own profile in a customer or partner community
Without restrictions on what to extend, subtabs really give developers the ability to deliver any functionality desired within the constraints of Visualforce. And knowing that the profile user's Salesforce ID can be retrieved from the sfdc.userId URL parameter, developers can provide a fully personalized experience for the user.
