Don’t touch that subject line!
Sunday, January 22nd, 2006Jason Clarke takes exception 
to an often-repeated productivity tip (e.g. on Lifehacker ) that subject lines should be edited to reflect the content of the message.
He points out that this will bust the threading on Gmail and other email clients (like Mail.app - as Greg rightly points out in the comments, Mail.app is not fooled by edited subject lines, but lists all the messages in the same thread.)
So the short term gain of added communication has to be balanced against the longer term loss of archive and search functionality.
Tags: Apple Mail, archiving, edit, GMAIL, mail.app, subject line, threading