[zeugmasyllepsis]

Persisting it on the server allows users to browse on multiple devices and keep their collapse settings in sync. This is useful in particular for long threads of comments, where collapsing can be used as a tool to keep track of progress through the thread by collapsing comments along the way.

[mintplant]

FWIW, you can still do this with the `<details>` tag, though. Have the page background-sync collapsed statuses back to the server and have the server remove the appropriate `open` attribute from collapsed `<details>` on subsequent page loads.

[pg_bot]

Sure I get that this is possible given that you know this is what the code does but the bigger questions are who knows that you can do this, and who actually uses this feature?

Is this the expected behavior when you collapse or show a thread? I would suggest that it is not, as most minor interactions on a page are only stored locally.

How many people actually use this feature? In order get a benefit from this feature you have to be logged into hacker news on multiple devices, collapse a thread on one device, come back to that thread later on the second device and then continue reading from where you left off. Alternatively you can just scroll past the stuff you've already read, which has a minimal cost to the user.

The benefits seem negligible for the amount of developer time that likely went into making this feature.

[Yoofie]

> Sure I get that this is possible given that you know this is what the code does but the bigger questions are who knows that you can do this, and who actually uses this feature?

I do.

> In order get a benefit from this feature you have to be logged into hacker news on multiple devices, collapse a thread on one device, come back to that thread later on the second device and then continue reading from where you left off.

I actually do exactly this. I read on my phone/laptop and later come back to the same thread (when more people have commented) on my home computer, usually at the end of the day. Having threads of conversation that you are not interested in already collapsed on multiple devices is very useful.

> Alternatively you can just scroll past the stuff you've already read, which has a minimal cost to the user.

Scrolling and quickly scanning over multiple threads is more time consuming and becomes actually annoying if you just want to passively follow a thread. If you want to follow multiple threads under the same topic, you either have to remember unique words/usernames/dates of that thread or resort to scroll & scan method mentioned above. One is annoying, the other is simply non viable for N amount of threads.

Until there is a way to subscribe to a thread, this feature is super helpful. Its actually just as good or better than a subscribe mechanism because atleast you can avoid getting multiple notifications for every single comment that get posted in the interesting thread. In the current scheme, all the irrelevant ones are already out of your way.

[yorwba]

> you can just scroll past the stuff you've already read, which has a minimal cost to the user.

Both vote count and age influence the order of comments, which means that the stuff you've already read may appear below stuff you haven't read yet.

If you use the feature at all, I'm not sure why you wouldn't want collapsed comments to be in sync across devices.

[doomjunky]

Actually i use the collapse feature for totally diffentent use case: Navigation.

I don't want to scroll over all the replies just to find the next post or i want to see all replies to one post. Therefore collapsing is convenient, but the slowth is annoying.

[anigbrowl]

That sounds like a solution in search of a problem tbh