How to Share Screens on Your Mac
Now suppose that you and your buddy both have Macs and want to toil together on a website or some other project from far away. If you both have Macs dating back to Leopard (or newer), you can work on one screen or the other; just click back and forth to swap screens. This stunt works in AIM, Jabber, Google Talk, and Bonjour but notably not in iMessage or Yahoo!.
Choose Buddies→Share My Screen with name of person (or phone number), or choose Buddies→Ask to Share name of person’s Screen. Rest assured that you can politely decline if you’re the one being asked. But positive thoughts, here, folks, so of course you’ve been given or received the green light.
You and your buddy can both run amok on the shared Desktop, even copying files by dragging them from one Desktop to the other. Messages keeps an audio chat going so that you can let each other know what you’re up to.
Not satisfied with what your chat buddy is telling you? Press Control+Escape to put an instant kibosh on the screen-sharing session or click the X to close.
If you’re sharing the other person’s screen, you’ll notice your own Mac Desktop in a tiny window.
As you might imagine, this screen-sharing business can get a little too close to home, especially if you don’t fully trust the person you’re letting loose on your computer. Be especially leery if someone who’s not in your buddy list comes calling with a screen-sharing request. You should also be careful before granting permission to someone from your Bonjour list. People aren’t always who they say they are.