A telemarketing service agency generally gives a business a lot of options and one of these is sales lead generation. This is when they have a list of numbers from different localities and they call these numbers to see if the individuals are interested in buying a certain product or service. These calls are not made to actually sell in most cases but are made to perhaps make appointments for a sales representative to visit the person or for a business member to call them back. It is a good way to increase sales by weeding out those interested in the product or service.