GMail supports labels as folders. When you create a new label it will ask you if you want to nest the label under another label and you can do this repeatedly to make a nested folder structure.
Crucially, this will show up as nested folders via IMAP.
They should use IMAP labels. Their IMAP implementation has always been terrible and broken. Anything you label gets put into an IMAP folder and therefore you download it multiple times per label.
I agree; fuck everything about gmail usability. It was a cool trick when it came out. Now it's just overly bloated AJAX, non-standards compliant garbage.
No, no - I understand that you can think this, and that they claim it, but from a UI angle, it's wrong. I hate the implementation of labels.
They don't actually disappear when I click on inbox. When I want my inbox, I want just that folder - all filtered content goes elsewhere and disappears until I want it. That's not GMail's way.
I have a giant folder hierarchy in my gmail, so I assure you this can work.
In your case it sounds like you're taking a message with the "Inbox" label and adding the "some/folder" label, which will indeed still show it in both places. If you move the message, which removes "Inbox" and adds "some/folder" it will no longer show up in the Inbox.
GMail supports labels as folders. When you create a new label it will ask you if you want to nest the label under another label and you can do this repeatedly to make a nested folder structure.
Crucially, this will show up as nested folders via IMAP.