The subject line is the most important part of your email. It’s perhaps the source your readers use most to decide whether your message is spam or not. The other is the sender line, your own name and email address.
If you’re writing to a friend who recognizes your email address immediately (and are you sure they can, by the way?), then maybe you can get away with a subject line that says nothing, such as “what’s happening?” or “just a thought” or “how’s it going?”
But spammers love to use those same meaningless subject lines. Anybody can, because they don’t say what the email is about, and they allow spam to be mistaken as personal messages. So for important emails, avoid this sort of unprofessional subject line. Unless you’re a spammer. Because you may get mistaken for one.
Vague subject lines also make email hard to catalog and find later. Suppose your prospective business client does recognize your email address. Or, armed with the latest spyware and virus updates, your customer decides to take a chance on opening your message which you have cleverly titled “Who knew?” Suppose it has something important to say. I hope you had something important to say. When your customer rereads the subject lines, looking for the email containing the time and place where he was supposed to sign your $1.3 million contract, how in the world is your customer going to remember which email it was? Was it “Who knew?” or could it have been “Update!” Well, you didn’t really need that $1.3 million anyway.
Today, most email is spam, and your email subject line needs to authenticate your message as non-spam. Being specific and personal is the best way to do that. Put something in the subject line that a spammer couldn’t guess: specific names or keywords that would interest your reader. And when you do that, you really are interesting your reader at the same time.
Yes, detailed subject lines may seem less personal. But drastic times call for drastic measures. In a sea of spam, a clearly-written email subject line rises to the top like a message in a bottle that says “Rescue me!”