Note: To enable comments the workspace administrator must go to Settings > General Settings > Configuration Options > "Enable Comments" > Yes
By default comments are listed oldest to newest down the page. The comment sort can be changed to newest or oldest first. The sort option is available at the top right of each comments section.
Here are a few examples of where you will find the comment sort option in different areas of the system
Comments in Files & Discussions
Comments in Wikis, Databases & Project Management
When you reply to an individual comment it creates a threaded comment. These replies are always listed from oldest to newest below the original comment. Read more about threaded comments