Important emails

[André Rodier]

Hi,

Sorry if I am not posting on the right mailing list, but I need email 
and especially IMAP experts opinion.

I have developed a small perl script for Amavis that tries to recognise 
business emails from bulk & mailing lists, in order to promote 
'important' emails, ala google. This is a feature I found very useful in 
corporate environments, where a lot of users are receiving 
advertisements, but not consider it as spam. (For info, the code is 
here: https://github.com/arodier/emclass)

My script add an email header (X-Email-Type), and dovecot uses a virtual 
folder called 'Important' to present them.

I know there is IMAP labels, and they are server side stored. I have 
successfully played with Thunderbird, but IMHO, it's not very reliable. 
The name of the label is the responsibility of the email client. As a 
result, if one client decided that $Label1 is 'Important', and $Label2 
is 'Business', other clients should be configured exactly the same.

I wonder if there is some norm - or convention - to attach labels to 
email headers, or if such a header exists, for instance a header called 
e.g. 'X-Tags', 'X-Keywords' or 'X-Labels'.

So, once stored, an email could contains - for instance - a header like 
this:

X-Tags: Travel,Advertisement,France.

Then, it would be easy to have server side search for labels.
Thanks for your feedback.

Kind regards,
André.