To promote conversation that’s focused on the topic of the original post, replies are chronological (not hierarchical or threaded). This reinforces the idea that replies are to be considered in the entirety of the conversation and it discourages off-topic tangents.
Tips
When replying to a topic, remember to keep your reply on-topic and meaningful to the entire conversation.
Add context to your posts by using quotes. You can highlight the text of any other post and you will see an option to “Quote” it. Click on the ‘quote’ button and the text you highlighted will appear in the body of your reply. This way you can respond to many people and ideas in a single post. Quotes are awesome; use them.