The only real selling point is it allows you to distinguish users apart from one another really quickly in a threaded conversation.

Sometimes someone other than the original commentator replies and unless you're paying attention to the user names you may make a presumption based on assuming they're the same person.

I kind of like that on HN I read through without necessarily paying attention to who is who. I focus on the comment or discussion rather than the personalities, and if I want to argue with a person rather than a point I have to go back & look at which comments are theirs.

It could be simpler to use a different color for their name, like with new users having a green color: When a user comments more than once in the same subtree, change the username color in all their comments. Leave single commenters as grey.

This should be pretty easy to do with a greasemonkey script.

The unofficial HN mobile app "Materialistic" does something similar to this.

It's a way to personalize your account and a way for people to easily recognize an online identity across comments, articles and communities. It helps you discover that @asaph on HN is the same person as @asaph on GitHub, Twitter, Stack Overflow, etc.

One of the features of HN is that identity is downplayed. Personally, I think that this encourages engaging with the arguments that someone makes, rather than who they are.

It's also a throwback to the old internet where pseudonymity was normal. It's refreshing to see usernames like AdmiralAsshat and TooMuchToDo.

Why does it matter if they're the same? Identity is vastly overrated in my opinion.

it's a way to track you.