This will be system or update. A system message is automatically generated by the system and describes an action, such as "Kris Gale has joined the Geni network." An update message is a regular message posted by a user such as "Kris Gale: Hi everyone." Put simply, this indicates whether a colon will separate the body of the message from the sender's name in the web interface.

public string MessageType { get; set; }

Public Property MessageType As String

public:
property String^ MessageType {
	String^ get ();
	void set (String^ value);
}