For your initial reaction post, focus on what constitutes a collaborative interaction.
Do include some of the learning from the mandatory reading part and connect with one or more of the articles listed. Make sure you include references/sources in your posts.
https://www.interaction-design.org/literature/book/the-encyclopedia-of-human-computer-interaction-2nd-ed/computer-supported-cooperative-work
http://egerber.mech.northwestern.edu/wp-content/uploads/2013/10/2014_CrowdfundingWorkCommunities_CSCW_Accepted.pdf
http://fid.cl/courses/hci/collaborative/lda_quality_camera_ready.pdf