Ephemeral messaging apps such as Snapchat, Wickr and Frankly, all of which advertise that your photo, message or update will only be accessible for a short period, are on the rise….
The companies offering these apps might very well analyze their content and make that information available to advertisers. We don’t know how much metadata is saved. In SnapChat, users can see the metadata even though they can’t see the content and what it’s used for. And if the government demanded copies of those conversations — either through a secret NSA demand or a more normal legal process involving an employer or school — the companies would have no choice but to hand them over.Bruce Schneier