Andreas Dybwad found Showbie:

• Moderately improves attainment“The transparency makes it easier to remind the pupils (and send a hint to their parents) when a task hasn't been completed, thus increasing productivity, and thereby improving attainment.”
• Moderately builds student knowledge“Since all kinds of input can be shared with ease, spreading good examples is just a click away, and pupils learn a lot from their peers (and the opportunity to become a model for others to follow is a great reward and boosts the effort of some).”
• Significantly improves teaching efficiency and productivity“Teachers teaching the same subject in different classes give each other access and have the opportinity to copy lessons and tasks.”
• Does not significantly reduce teacher workload“Since everything the pupils produce is available to the teacher, some sort of feedback is expected with every input. Even though a lot more time is spent reading and watching what the pupils have handed in, the increased knowledge of their strengths and challenges makes it worth it!”