Help me understand iMessage! 😆

Today I was hard at work, using my job-provided Macbook Air. A long time Windows user, I get by on a Mac, but there’s a lot about it that’s still foreign to me.

Out of the blue I heard an iPhone-esque “ding” (no one in the house owns an iPhone) and my computer notifications displayed a message from a (personal side-gig) client I had been trying to reach.

Typically I contact him by email, but this notification was not an email notification.
I had recently also tried to reach him by text, but this was not a text notification from my Google Voice account. I was a little scared to interact with the notification for fear it would vanish and I’d lose this point of contact, since I really needed to follow up with him.

Clicking the “more” icon on the notification offered me the option to reply by text. But to what and using what? I was soooo confused.

I finally clicked on the notification itself, hoping it would do something other than slide off the right side of my computer screen, and to my amazement, the computer opened up an iMessage interface where I could reply.

Okaaaaay. :confounded:

What is going on? How did this guy find me and address a message to me using iMessage? What info is my mac publicly broadcasting about me that made this possible? I mean, I’m glad to have a communication channel with my client that works for him, but I’m a little nervous about what this means as far as what personal info is widely visible to the world.

Could someone with some iMessage experience please help me understand how this person found me this way?

Could someone with some iMessage experience please help me understand how this person found me this way?

iMessage works with email addresses as well as phone numbers. You don’t need to know someone’s phone number to exchange iMessages.

On Apple devices other than iPhones, iMessage is intended to use email addresses. Correspondence takes place using the devices’ (Mac, iPad, Apple Watch) Messages app.

If one also has an iPhone, then Apple devices other than the iPhone can exchange iMessages (and SMS/MMS) using the iPhone’s phone number. It’s similar in concept to the old Republic Anywhere and was among the reasons I was a fan of Anywhere.

So are you telling me that my client (let’s call him Fred), opened iMessage on his iPhone, entered the gmail address he has for me, and sent the message, and that the message was then delivered to my computer’s iMessage app… and if so, where does this connection exist between the gmail address Fred has for me and my computer’s iMessage app?

Except, for a Republic Anywhere message to reach my computer, I had to install Anywhere and log into my RW account.
I don’t know that I’ve taken any similar step to associate iMessage with my gmail address. In fact, I didn’t even realize the computer had an iMessage app, so I don’t understand how it has associated me, the user of the computer with me the owner of a specific gmail address.

Since you know one of my gmail addresses, are you able to send me an iMessage?

No, your contact information shows green not blue. Let’s see if we might unravel the mystery. Is the email address “Fred” is using associated with your Apple ID (Apple’s version of a Google account for those following along)?

Indeed, it is. :thinking:

So, are you able to “find” me only if you have that email address in your contacts already?

Mystery solved. Just as Google promises “one account all of Google”, Apple IDs are “one account for everything Apple” (including iMessage). That said, if you wish, it’s possible to prevent “Fred” from reaching you via your Mac’s Messages app:

  1. Open your Mac’s Messages app
  2. Under the Messages menu, select Settings…
  3. There you’ll see email addresses and/or phone numbers at which you’re reachable. Phone numbers require an associated iPhone but email addresses do not.
  4. Uncheck the box next to any email address you do not wish “Fred” or anyone else to be able to message you at

No, if I knew the other Gmail address or you associate the Gmail address I do know with your Apple ID, I could send you an iMessage by entering the email address in the To field rather than a phone number from the Messages app on any of my Apple devices.


Since it seems to be the only way Fred knows how to reach me after all these years, I’ll leave it as is until I close out that account.

You’re welcome!

This works both ways. You could send your iPhone friends iMessages from your Mac to their iPhone phone numbers. They would see blue not green bubbles. If they weren’t paying close attention, they might think you had switched to iPhone. :joy_cat:

Of course, if you would prefer others not know the Gmail address in question, you shouldn’t do this.