My company uses it at work. We had Verizon set it up as the "roll to line" and it picks up when all the other lines are busy, takes a voice message and sends it to our email. Of course we use it when ever we can for out-going long distance because it a flat monthly fee.
It includes a second line for our FAX machine.

Works best if you have a very fast DSL or cable ISP internet provider.

hope this helps,
Dennis