We learn form each others' contributions. We can then add our own thoughts on the topics etc. We can also analyse and provide alternatives to topics, this helps to bring up new topics and widen the scope of the question we are endeavouring to answer. When in class we can talk to each other as well, teach each other new things we have learnt by trial and error of our own. We have learnt that the most effective way of learning is to teach it to someone else, this reinforces it in your own learning and you remember it much better when you gain the satisfaction of teaching it to someone else.