Hi,
What if right/left clicking on a user you get a context menu of actions you can do with that user? For example, we already have the email (or if email is filled) we can show "Send Email"...clicking on it just uses the regular intent/link for "mailto:" and we let the OS take over from it.
Was also thinking, what if in integrations we enable user action integrations? An integration of this type will require a name to be shown in the user actions, a "field" to be requested to the users (they fill when desired) on their profiles, a URL end point that can support inserting the originator user and target user.
For example, we could create one called "Call via Skype". The integration will offer the users in their settings to enter "Skype User". The end point will be a "skype:{target}?call" The context menu (mentioned above) could then display "Calll via Skype". We could create another for Hangouts, phone numbers, etc. Because of web intents/custom protocols, we can do this easily.
I got inspired on Slack new feature of "Call".