A number of news apps are experiencing new growth or a resurgence in monthly active users likely attributable to tests Facebook is conducting in News Feed.

As we’ve seen earlier this year, tweaks in Facebook’s algorithms or changes in design can have a major impact on how many users visit certain apps. Lately, we’ve seen a larger version of the “trending articles” module that suggests news stories based on their popularity among other Facebook users.

The social network has experimented with several different layouts for this feature, including one recently that showed only one article at a time. After this was introduced at the end of May, many social reading applications saw their monthly active user numbers decline, according to our AppData tracking service. Since August, however, Yahoo Social Bar and Washington Post Social Reader picked back up. Smaller news apps like those from NBC News, Wall Street Journal, CNN, Mashable and Grantland, which had relatively static growth through July, have also been on the rise in recent weeks.

Besides the larger format some users are seeing for “trending articles,” Facebook seems to have eliminated the icon that indicated whether or not the user’s reading activity would be shared by clicking on the link. It’s likely that icon deterred users and contributed to these apps’ loss of MAU. With these types of experiments out of developers’ control, it is important to consider other factors to understand an app’s actual level of success. For example, some media outlets may be reaching a demographic  that wasn’t coming to their site before the Facebook integration, or increasing the average number of articles and time spent on site by each visitor.

In addition to the trending articles module for apps that integrate Open Graph, we’ve also seen Facebook test new layouts for how articles appear after users click the Like button on third-party sites.