Calling contact's computer on Yahoo! Messenger

What does call contact's computer mean on Yahoo! Messenger?

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“The gladdest moment in human life, methinks, is a departure into unknown lands.” – Sir Richard Burton

What happens when I call my contact's computer? It seems impossible to call a computer.

It's the same principle as instant messaging or email: exchanging data between computers. But, in this case, what's being exchanged is audio instead of text.

Depends on the time of day. If you call a computer late at night, it usually believes you've made a booty call, in which case the computer will want your address and preference of lube.

During the day, it usually never picks up or it will go straight to voicemail.