Facebook is re-launching an app called Study which pays users over 18 for data on how they use competitor apps.
The market research programme allows Facebook to gather data about the apps installed on users' phones, the amount of time they spend on those apps, and what activities people are performing on those apps.
"It does not collect user IDs, passwords, or any of the participant's content, such as photos, videos, or messages," Facebook said, although the demanded permissions for the app could allow it to attempt to collect such content.
"We also don't sell information from the app to third parties or use it to target ads, and it is not added to a participant's Facebook account if they have one," the company assured.
The programme was previously introduced under the name Onavo and was widely criticized for paying youngsters to install the software and "spying" on them by accessing every activity on their phones.
The controversial programme was shut down following the uproar it caused.