The strongest effects have generally been found for service learning programs that have the explicit aim of developing active citizenship, in contrast with those that emphasize community service and character building
Time's annual series on the future of something. This year it's work and the workplace. Especially interesting is the notion of where will work will occur.
In case you were wondering if what you were doing with your students this year has value, read through some of the changes to the idea of work that some experts feel they will go through shortly.