The text message will be sent as an email to SMS using each group member's mobile number and mobile carrier (e.g. "firstname.lastname@example.org"). To select the mobile carrier for each group member, edit the group member's directory profile and select the mobile carrier. The directory profile edit page includes a link to perform a carrier lookup. This manual step makes it possible to send free broadcast text messages (a lookup service that can be accessed dynamically requires a per message service fee). If a carrier is not specified for a particular group member, the message will be sent to the member's mobile number at each of the major U.S. mobile carriers (AT&T, Verizon, Sprint, etc). Note that this will result in rejected email messages to the sender from the incorrect carriers.