Custom Field: Are messages sent to a set of Subscribers.

Broadcast: Are messages sent to a set of Subscribers.

Message: Is an individual communication sent to or from a Person.

Participant: Is a Person who has one or more mobile interactions, such as sending a text message, with a company but has not yet subscribed to a Subscription List.

Pending Subscriber: Is a Participant that has requested to opt-in to a Subscription List, has been sent a prompt to join a Subscription List that has not expired, but has not yet confirmed their opt-in.

Person: Is an individual in your Mobile Database.

Recipient List: Is an externally defined set of Persons that is used to  target outbound content delivery.

Standard Field: Are messages sent to a set of Subscribers.

Subscriber: Is a Participant who is subscribed to one or more Subscription Lists.

Subscription List: Is a collection of Subscribers that have all subscribed to the same type of certain content.

Tag: Are messages sent to a set of Subscribers.