Of course it's worth responding. And it should be done something like
this.
I too always ask myself, why they always seem to come back. Either for your attention/company, for not feeling guilty about dumping you in the first place or because of the best sex they ever had.
@HBK: Guess it all depends on the girl. I think it won'T make a big difference where you live. People in general becoming more superficial these times. Companies firing employees by email or have them escorted out of the building without their bosses ever showing up. I heard of people who learned in the news that their job and their company is gone. Most people avoid unpleasant things.
Been dumped by email, by SMS. In my younger years ( pre-cellphone and pre-www ) by a friend of hers telling me on the phone. However i have also been given the classic "Dear John" letter. A face-to-face conversation ( or monologue ) is the rare case.
I'm not much of a dumper. Guess i'm too slow. But whenever it was necessary, i did it face-to-face.