When a computer user adds their email address to a mailing list (newsletter), the user is subscribing to whatever is being sent to that mailing list. In some cases, subscribing involves the entry, or registration, of an email address on a web page. The email address is added to a database that contains other email addresses and is used to mass mail some form of digital content. Receiving daily offers or coupons or weekly updates from various companies are some of the uses of subscriptions.
When customers subscribe to a magazine, some companies offer online, or digital, content with that subscription. This online content is included with the magazine subscription, providing customers with the option of viewing the magazine content online. It may also include additional content not available in the printed magazine.