Q: I've gone on five dates with a guy over several weeks, but we haven't formalized our relationship. Now I want to break up, but I'm wondering if I need to officially do that. If so, I know I probably shouldn't do it via e-mail, but do we have to talk in person?
The short answer is yes, you do -- kind of. On one end of the ethical continuum -- the cold, dirty end -- is the complete unacceptability of just vanishing on someone you went on three or more dates with. This many dates is a collective time commitment, and you should honor both of your investments -- not to mention his feelings -- by verbally addressing that it's not working.
But verbally addressing that it's not working isn't the same thing as "breaking up," a phenomenon closer to the over-honest other end of the continuum. There's a trend -- an ugly effect of eBay or something -- toward excessive returned-merchandise feedback. Your parting of ways should be direct and sensitive, without trying to quantify something as subjective as another human.
Avoid being specific when explaining why someone you don't really know isn't right for you. Anything you've decided about him in a few weeks is too premature to be constructive criticism: too old, doesn't own a TV, or his kisses make you gag. Call me oversensitive, but I don't need to hear that I'm too hairy (as one fella pointed out). I'd prefer a general "This just isn't working out." Then I can blame the other person, buy new jeans, and move on.
Lastly, you don't have to end things in person, but it's tacky and inhuman to do it via e-mail. Pick up the phone. And no, you can't leave a message. Keep the call to three minutes, have a vodka shot nearby for the awkwardness, and jump back into the dating pool feeling good.