updated 04:39 pm EDT, Wed August 20, 2014
Includes blocking, audio controls
The sixth OS X Yosemite beta enables promised screensharing via Messages, a report notes. The feature requires simply that a person have an iMessage or Apple ID account. Some options include turning audio conversation on and off, pausing sharing, and blocking requests from a particular user.
Users can even allow a person to take control of their screen. For security's sake, this requires a second authentication. Screensharing was a feature in Apple's now-defunct iChat, but required an AIM, Gmail, Jabber, or Yahoo account.