Systems and methods for sending a message to a plurality of a client's users prioritize delivery of the message first to those users who are most engaged with the client. A user's degree of engagement with the client may be determined based on a variety of factors, including how recently the user interacted with the client. A database query of user contact information may result in query results being streamed to a message sending unit, and the streamed results may be ordered based on the user's degree of engagement.