Subscription learning doesn't have to be about information. It can directly or indirectly prompt actions. In a recent field study, a one-sentence text produced results. Here's the abstract from the journal:
"Parental involvement is correlated with student performance, though the causal relationship is less well established. This experiment examined an intervention that delivered weekly one-sentence individualized messages from teachers to the parents of high school students in a credit recovery program. Messages decreased the percentage of students who failed to earn course credit from 15.8% to 9.3%—a 41% reduction. This reduction resulted primarily from preventing drop-outs, rather than from reducing failure or dismissal rates. The intervention shaped the content of parent–child conversations with messages emphasizing what students could improve, versus what students were doing well, producing the largest effects. We estimate the cost of this intervention per additional student credit earned to be less than one-tenth the typical cost per credit earned for the district. These findings underscore the value of educational policies that encourage and facilitate teacher-to-parent communication to empower parental involvement in their children's education."
Kraft, M. A., & Rogers, T. (2015). The underutilized potential of teacher-to-parent communication: Evidence from a field experiment. Economics of Education Review, 47, 49-63.