First and foremost, it is in the group discussion and exchange that we students can have a thorough idea what our peers are reading for the moment, serving as a driving force for our own reading journey.

what从句为间接疑问句，作idea的同位语，疑问词what在从句中作宾语。what从句前省略了介词of。如果介词of不省略，则what从句为介词of的宾语从句，介词短语作idea的定语，表示同位关系。

serving现在分词短语为补充性状语，对整个主句作补充说明。该分词短语可以改写为which引导的非限制性定语从句，which的先行词为整个主句内容：

，which serves as...