As you’re about to discover, Messages is like an MP3 toothbrush or a carboat. It’s a hybrid app—two very different functions mashed into a single body.
First, Messages is your Mac’s gateway to iMessages. They’re a lot like text messages on cellphones, except for the following:
They’re unlimited and free.
There’s almost no length limit.
They can include photos, videos, and other huge files.
They can go to Macs, iPhones, and tablets—and, in fact, they appear simultaneously on all of yours.
Unlike traditional chat, your pal doesn’t have to be online to get your message. An iMessage will be there when he turns his gadget on again.
The only requirement is that both of you, sender and receiver, have to have iCloud accounts (Chapter 17).
But Messages also does what its predecessor, iChat, did: It’s a traditional chat program, capable of exchanging audio, video, and typed messages with people on other chat networks (AIM, Yahoo, and so on).
This chapter covers both of these major functions in turn. First up: iMessages.
All right. You have an iCloud account, and you have at least one Apple machine. The first time you opened Messages, you were asked for your iCloud address (and offered the chance to get one). If you bowed out, you can still fill in that info in Messages→Preferences→Accounts. Basically, Messages keeps demanding your iCloud or Apple ID until you submit. See Figure 20-1.
Figure 20-1. You have to specify an email address to anchor your iMessages life. ...