TextMarks is a FREE service that allows you to create a subscription code via the TextMarks website www.textmarks.com so that anyone who text messages that code to the TextMarks number 41411 will subsequently be registered as a part of your distribution list. Then whenever you need to send out a text blast, everyone who has signed up will receive the messages you send.
This is a really useful service with lots of real-life applications, especially if you help coordinate medium-to-large groups of people during short-term events. Think disaster recovery situations (Sanjay?), church mission trips (Chuck?), big scavenger hunts, competitive events,...basically any event during which you may need to send out impromptu instructions or alerts.