Talking via Messages and FaceTime
OS X comes with the Messages application, which you use to exchange instant messages with other OS X users, as well as anyone with an iPhone, iPad, or iPod touch. You can also use FaceTime to make video calls to other people.
OS X includes the Messages application to enable you to use the iMessage technology to exchange instant messages with other people who are online. The first time you open Messages, you must run through a short configuration process to set up your account. ...