subscription(A request for a copy of a publication to be delivered to a subscriber; Part of the application metadata that specifies the data source, the refresh interval, and, optionally, subscription expiration; A request for a copy of a publication to be delivered to a Subscriber; An agreement in which a customer prepays for periodic or regular services)
POP subscription(A subscription that gathers messages from POP3 mailboxes and delivers the messages to a designated Outlook Live mailbox so that the Outlook Live end user can centralize their e-mail accounts and only have to check one mailbox)
RSS Subscriptions(A feature that enables a user to capture all of the RSS feeds they subscribe to in a folder that automatically updates at specified intervals)
forbes.com Alex_Odeychuk)