What they describe is almost exactly GroupMe, circa 2010. Group chat app, uses SMS so it works on non-smart phones, no signup required--just text /add [number] to add someone to the group, and they're auto-joined.
Not to say it'll work for them, or that things haven't changed since 2010, (group chat market saturation, more smartphones) but it was a pretty good idea at one point.
Not to say it'll work for them, or that things haven't changed since 2010, (group chat market saturation, more smartphones) but it was a pretty good idea at one point.