Please correct me if any of RSS/Atom/etc. do already have threading.

On a mailinglist I'm on (large number of subscribers, and often threads become quite long but only interesting for like 1% of subscribers, but with days with now new mails inbetween) there is a discussion every now and then by people who'd prefer a forum.

A forum however is a totally non-working solution. First of all, web UIs (even Ajax, Web 2.0) suck. None offers threading as comfortable and smooth as a real email reader such as Evolution or Thunderbird (Outlook seems to have quite bad threading, or disabled by default, thats why many novice users think forums do better threading...).

Secondly, a forum requires you to frequently visit it, whereas email will patiently sit in your email folder waiting to be read, just like your regular email. That is much more workeable with an increasing number of lists/forums.

You can easily be subscribed to 20 mailing lists. Can you imagine visiting 20 forums every day? Even with smart browser (e.g. Galeon that can open a bookmark folder into tabs, did I mention IE sucks?) this is quite a pain. Now imagine that some of these forums are inactive for weeks. Visit the forum just to see that there are no new posts?

Now RSS comes into mind. But for a Forum? Should it list every post? No, it needs to have thread support, so I can easily kill whole threads.

Or I'll just stick with email and tell everyone who wants a forum to fishing. Or write a forum with reasonable email support.

Oh, and RSS doesn't solve the writing problem either. No, RSS is not the answer. Email is.

Update: A couple of people have send me emails about NNTP/Usenet/News. While there are excellent clients for it available, and the distributed nature is also a nice feature, it also has drawbacks.

For example, you basically need to setup a separate service (especially if it's a private newsfeed, and you can't use gmane), which is much more difficult that running a mailing list or a RSS feed. You can run a RSS feed with basically any provider. You can get a private mailing list with many. Then you usually need to setup a new profile for each NNTP server, because it's designed totally around the server model, not single groups. Furthermore, while you can usually access RSS feeds with your regular web browser (in form of their HTML counterparts, or some built-in filter), and mailing list with your email program, users need separate software for using News at all. (Granted, many email clients can do news) Oh, and then people seem to be afraid of NNTP, unfortunately.