An ADAD is an Automatic Dialing and Announcing Device. It's a computerized machine that holds a professionally recorded message and delivers that message to anyone who has a telephone. It can even deliver messages to answering machines without any supervision at all. It can be used to advertise, generate leads, make sales, notify, remind and alert. ADADs generally run unattended. However they can also be manned by a live operator who can ask permission to play the recorded message of the called party. The attendant can also stand by and "close" the sale if the prospect has indicated an interest in the product or service by pressing 0 on their touchtone phone.
You can enter individual numbers into it which can receive specific messages. Or you can put it on a prefix, give it a beginning number (as 555-0000) and ending number (as 555-9999) and it will automatically dial every number in between. No other method of advertising or generating leads is as cost effective in the world today.