Audio signals can also be sent using microphones and speakers. This means you can see and talk to another user.
Companies can set up meetings with eyeball-to-eyeball communication between people who are not in the same room, building or even country!
Pictures are a bit 'jittery' at the moment but advancing technology will no doubt improve this! A broadband connection is essential!
Care has to be taken about when conferencing takes place because of time differences - mid-morning in one country may be midnight in another!