Snapchat yesterday launched its biggest update yet, which added disappearing texts and instant video calls to the ephemeral messaging service. High school teacher Tracie Schroeder tweeted that her classroom nearly descended into anarchy after students got the update. In 16 years of teaching I cant think of anything that has ever disrupted my classroom more than todays @snapchat update. — Tracie Schroeder (@bravesearth) May 1, 2014 Instagrams new Instagram Direct messaging service, for example, didnt make much of a splash.