When I first saw that gmail starts a new thread when you change a subject I did not believe it at first; I thought I have made a mistake in replying. Text-based clients of old (tin, pine, etc.) still outperform current monstrosities by a wide margin.
And of course, there's nothing stopping anyone from building a web forum and offering an endpoint for third party clients, they just don't, mostly because web forums themselves have more or less been superseded by Facebook, Twitter and Youtube, and no one seems to care about them anymore.
The only pre-web feature that web forums can't really implement is decentralization.
One of the things we keep forgetting as we move forward is that client-control > server-control.
I'm not sure if we're forgetting it, as an industry we seem hell bent on removing user control. SaaS, cloud hosting, software walled gardens, invasive automatic updates, hidden software in hardware, etc. We're losing more and more control all the time. Around here it's nearly heresy to suggest the companies run their own servers.
There's a clear agenda to take back the power and voice that the computers are giving to the common man: http://opentranscripts.org/transcript/coming-war-general-com...
"This is one of the things that web-based forums have yet to get right. Email (and NNTP news) clients from 20 or 30 years ago are far superior in this respect, because they can intelligently deal with threading and folding. These features alone makes large conversations much easier to deal with than on web-forums.
To add to that, email (and NNTP news) clients even from 20 or 30 years ago have other powerful features that web forums have yet to catch up on:
- kill files[2] (which you can use to filter out unwanted articles/mails based on content or metadata such as subject, user, etc)
- scoring
- user-configurable anti-spam filtering or other "intelligent" filtering (such as bayesian filtering not just for spam/ham, but for interesting/unintersting content)
- tagging not just on a site-wide level but at the client level so each user can tag messages/articles the way they make sense to them
- other advanced filtering and scripting based on any of the above
Web-based forums are just incredibly primitive compared to this many-decade-old technology."
[1] - https://news.ycombinator.com/item?id=15373179
[2] - https://wikivisually.com/wiki/Kill_file