A circular letter is a written communication that is intended to be sent to a group of individuals. It is often formal and formal. It might be for a small group or for broad distribution. A circular can be a newsletter, postcard, e-mail blast, or other type of communication. The term "circular" comes from the fact that it travels in a circle, being delivered to each recipient. Circulars are used by organizations as a means of communicating with their customers, notifying them of changes to services, discounts, events etc.. They may also use circulars to promote new products or initiatives. Circulars are sent out periodically, most commonly once per month, but sometimes more frequently or less frequently depending on the nature of the message. Organizations that send out many circulars usually call them "newsletters". However, this is not always the case; some companies only send out one or two circulars per year while others may have a monthly magazine or website update that functions as a circular. There are two main types of circulars: customer communications and corporate announcements. Customer communications may be special offers or promotions for existing customers. Corporate announcements may include changes to an organization's product or service offerings, news about upcoming events, or any other important information that needs to reach all customers at once.