in reply to Email subject lines should be written:

Other: "unsubscribe" ;-)

Seriously though, I write the subject first, then the body, then I rewrite the subject for clarity if I see that it doesn't include the necessary info to classify the message at a glance.

Good: "(server name) downtime next friday (date)".
Bad: "(server name)", "Server downtime", "Friday".
Worthless: "hi".
Unforgivable: "IMPORTANT!!!!".

-- Time flies when you don't know what you're doing