Foonz is a slick tool that lets you communicate with a whole group of people all at once. While there are other services that let you set up conference calls, Foonz lets you do it "on the fly". Sign up for a free account, and when you need to get in touch with a bunch of people at once, maybe to plan the evening or to touch base on an upcoming reunion, you call in and pick from your list of contacts. Foonz sends them a text message with a number to call that will connect them instantly with you. Or if you don't have time for a call, or you're giving out some non-time critical information, you can leave a message for your contacts all at once, rather than having to make a dozen calls and leave a dozen messages.
Foonz is a free service. You have to pay for the call, but even that is cheaper than having to make all those individual calls to everybody on your list.