[ Version ( since = "0.4.0" ) ]
public string protocol { get; set; }
Identifies the IM network.
For example: gdata_gd_im_protocol_jabber or gdata_gd_im_protocol_google_talk.
For more information, see the <ulink type="http" url="http://code.google.com/apis/gdata/docs/2.0/elements.html#gdIm">GData specification</ulink>.