I’ve sent enough unanswered emails to know that people under 21 just don’t check their email accounts. Or maybe they look at them once per week. What do they check? Their phones. So some teachers have taken to texting students what otherwise might be emailed: reminders, assignments, and the like. I would recommend the following apps for this purpose: the first is Remind101, which was developed for education. You set up a class, following the same procedure as you would for an older course management system such as Nicenet. Remind101 generates a code, which students then add via their own smartphones. Soon, you can send reminder texts and more to your entire class. Nice.
Of course, smart phones already come with ability to text a group of users. In both Android and IOS, you just keep adding contacts (or new numbers) to the recipient box. That’s not a bad way to go, but if you want a little more, check out GroupMe, a service that makes setting up group texts a little easier. Set up a group via the web or the mobile app, and GroupMe syncs it all. It’s nice to send text messages via the web, too, especially for people over 42 who just don’t text all that well.
Of course, standard text rates apply for both, which is not the case for Viber. If I understand it correctly, Viber can send texts over the web, in the same way that Vonage uses the web to make voice calls. Your school has a wifi network, so theoretically, you could communicate to students via Viber, provided they installed the app. Worth thinking about, at least.