[Geary] virtual folders and labels

[Federico Bruni <fede inventati org>]

Hi all

I think that vfolders are a great concept, which makes work on emails 
faster and more flexible.
IIUC the concept applied to email (my reference is Gmail), every 
message is saved in one folder once, but can be displayed in several 
virtual folders (aka labels). The advantages are:

1. no duplication, so no waste of space
2. easily and quickly mark a message with as many labels as you want 
(quick because you are not moving anything and you don't have to resync 
a folder)

I wonder if virtual folders is a feature that we should expect from the 
mail server or from the mail client. In the current architecture of 
Geary the answer is probably "the server should do it". But what about 
non-Gmail users?

1. Server support
I don't know any open source mail server software which supports 
virtual folders.

2. Client support
Thunderbird and Evolution should support virtual folders.
But I guess that this is a complex task and maybe Geary is not the 
right app for this kind of feature?
Some interesting discussion, quite related to this, here:
https://bugzilla.gnome.org/show_bug.cgi?id=714208


Thoughts?

Thanks
Federico