After you have asked students to publish their essays online, or to hold an online discussion, plan an in-class discussion about the role of "context" in writing a text.
Assign a brief writing assignment in which they consider how the context of publishing online made them feel as writers, what choices they made that might have been influenced by knowing their essays would be published, or how discussing online changed their approach to discussion. You could do this as a homework assignment, or possible an in-class writing assignment, with the former probably being the better option because it will give students more time to think about the role of context in what they wrote or how they discussed.