Sarah Perez at TechCrunch:

Onavo, the data-security app maker Facebook acquired in 2013 in order gain insights into mobile user activity across apps, has quietly launched a new app aimed at Android users called Bolt App Lock. Instead of offering a VPN, Bolt App Lock is a tool that lets you lock down any app you don’t want others to be able to open, using a PIN code, pattern, or your fingerprint.

But Onavo — and Facebook’s — primary interest isn’t on personal security. It’s about finding a way on users’ phones in order to monitor mobile activity and learn what new apps could be taking attention away from Facebook’s social network.