Mail archive

[Metagross31]

I often have a problem that some people might know.
I have a few mails in my mailbox, which I do not want to delete, but keep them, either because they have some important information or just for memories sake.
However, when I sell lots of cards on the auction house, my mailbox gets flooded with mail from the AH.
Now I am in the situation, where I either have to delete all mail manually or click "collect all", which would also delete the mail I want to keep.

Thus, I want to make the following suggestion:
Implement an option to archive mail, which then gets moved to a different tab in the mailbox.
Here is a quick UI mockup I did in gimp:

The idea is, that I can select a mail and click "Move to archive" to have the mail no longer appear in the "Incoming" tab, but instead in the "Archive" tab.
When I then click "Collect All", it will delete and collect all mail in "Incoming", but not in "Archive". When I switch tabs to "Archive", I would be able to see all archived mails, where I still have the option to read, delete or move them back to "Incoming".

[LEBOVIN]

Same for replies or mail you have send, accessing them I would love to see included in that archive or another tab.