I remember when Opera initially launched the concept in its e-mail client that you did not really need folders to organize your e-mail, but that it was sufficient to group them.
Fairly recently Google reviewed the same concept and defined the labels and a very similar way of organizing your e-mails. Google certainly added a very powerful search engine, but the original concept is very much the same.
Being a Mac user, I have been using Apple’s Mail for a few years now. Mail.app has a standard a hybrid approach to e-mails, the standard folders are available, but since Spotlight became part of the OS, users are also able to create filters and organize e-mails in “dynamic folders“.
I have never been a fan of Opera’s approach and the same applies to Google’s approach and Apple’s dynamic folders.
I really like the threaded view, though. Both GMail and Mail.app offer this feature.
For my normal inbox and for a few folders I use the standard view with e-mails sorted by date descending.
For mailing lists I just love the threaded view. Here are two screenshots of the same mailing list:
And here is another screenshot of the same mailing list with a standard view:
When you read and contribute to a mailing list with a fair amount of traffic and different topics discussed, maybe with a lot of replies to the same topic, the threaded view lets you have e-mails organized very well and lets you follow a full thread even if other e-mails were sent for other threads in the same timeline.
While both Google’s and Apple’s e-mail clients are not exactly perfect when grouping e-mails, it still is very helpful and works smoothly in most cases. I have been using this feature for a couple of years now and liked it. I realized how I’m not used to it when last week I read my e-mails using a web client and found myself lost in the e-mails, losing track and having a hard time identifying the context as I was moving through the list of my e-mails, but were actually about different topics.
Going back to check old threads is also very easy when using this feature as you immediately get all the e-mails together.