A neat thread list is for reading efficiency. Besides, a neat list is a good base to add necessary features on.
For designing the information in the list, we put the sender’s name on the first line, the content on the second line, and the email topic on the third line.
+ The sender is more important than the topic. For example, when you see 2 emails with the same email topic “Let’s meet tomorrow” from me and your boss, which one is more important to you? That’s why we choose to place the sender’s name on the top.
+ For the email topic, if it contains multiple emails, the topic won’t change that every time we receive a new email under that email topic. That’s why we place it on the bottom. Finally, we have a “who said what at where” structure which is more readable.