Wall Street Journal sources have also heard that Facebook will stop supplying data on the success of those ad campaigns to those providers.

This wouldn't have put a stop to Cambridge Analytica's activities (it harvested data under the guise of research), and Recode noted that it might create headaches for smaller companies that can't afford to collect their own data. However, it could reduce the chances that Facebook ends up buying data collected through shady or inaccurate practices. Whatever Facebook loses in terms of sheer data it might gain by avoiding another fiasco that leads users to quit the site.