Text messages are used for personal, family, work, business, and social purposes. In the 21st century, the sending of short informal messages became mainstream and an accepted part of many cultures, as happened earlier with emailing.[5] Texting is a quick and easy way to communicate with friends, family, and colleagues, including in contexts where a call would be impolite or inappropriate (e.g., calling very late at night or when one knows the other person is busy with family or work activities). Like e-mail and voicemail, and unlike calls (in which the caller hopes to speak directly with the recipient), texting does not require the caller and recipient to both be available at the same moment; this permits communication between busy individuals. Text messages can also be used to interact with automated systems, for example, to order products or services from e-commerce websites or to participate in online contests. Advertisers and service providers use direct text marketing to send messages to mobile users about things like promotions and order status, instead of using postal mail, email, or voicemail.