This photo-sharing app is taking hold among the youth, with 10 percent of teens in the world already on it. Snapchat users can take photos, record videos, add text and drawings, and send them to a controlled list of recipients. These “snaps” have a set a time limit for how long recipients can see them, after which they are hidden from the recipient’s device and altogether deleted from Snapchat’s servers. Think of it as a text message that self-deconstructs, which (heads up, parents!) paves the way for naughty behavior that would otherwise not be so willingly documented.