Telemarketing is a method of direct marketing where sales representatives contact potential customers over the phone to promote products or services. This approach allows businesses to reach a wide audience quickly and can be used for both sales and customer surveys. Telemarketing can be conducted through cold calls, where representatives call individuals who have not expressed prior interest, or warm calls, where they reach out to existing customers. While it can be effective, telemarketing is often regulated to protect consumers from unwanted calls, leading to the establishment of laws and guidelines governing the practice.