This is all very interesting. The drift away solution seems mean to me, but it might be lack of practice on my part.

You can tell someone things aren't working for you, without saying why.

The way I see it, the very fact that things aren't working is reason enough in and of itself. Saying "it just doesn't work" means there's nothing inherently wrong with either him or me, it's just that we don't fit. At least, that's the way I understand it, and usually only after the one (blind, in my case) date.

not that I've ever dated more than one person at a time

Once, friendA offered to set me up with guyA, and then was gone for a few weeks, so when friendB offered to set me up with guyB, I agreed as well, not feeling obligated to guyA anymore, seeing as he was missing. Of course, right then and there, guyA calls out of the blue. So I had two blind-dates in two consecutive evenings. It felt so very strange.

IIRC, I went out with guyA on a second date, after which we had the "it just doesn't work" conversation and parted ways as friends, but guyB had that conversation right after the first blind date. And that's my history as a more-than-one-guy-date-er.

[Edit: I don't know how to do the "drift away" thing, not just in dates, but in any sort of connection.]

Even with a real break-up, you don't have to explain. You might want to, but you don't have to. I HAVE dated more than one person, and you can either do the drift thing or say "It's been great getting to know you and hanging out with you but this relationship isn't working for me." They may ask why, and you can then tell them about the other guy/gal/marmot if you want to, or say something vague, like, lots of reasons.

Opinions differ, ita. I think it's emotional cowardice to go to the "drift away" thing. Although it's very very common in our society. I prefer clear communication. Someone not calling could be interpreted a variety of ways - it could be they got busy. But when someone says "Thanks, but I'm not interested in another date." (or however it needs to be phrased to best be politely candid), it's clear.

the very fact that things aren't working is reason enough in and of itself

But in the scenario about which I'm curious, it's not that things aren't working. It's that things are working better with someone else.

But that means it's NOT really working--if it was really working, you wouldn't be more interested in the other person.

What Robin said.

Saying "it just doesn't work" means there's nothing inherently wrong with either him or me, it's just that we don't fit.

Also Nilly. It's so true! And wouldn't you rather hear even a bullshit line than that you're boring or something?

But in the scenario about which I'm curious, it's not that things aren't working. It's that things are working better with someone else.

If they are a tool, they will demand to know what is going on, become a stalker, or just keep trying to contact you.

I guess I qualify for tooldom then, because if I like someone and am not given a specific reason to go away (mind you, "I'm not interested in going out anymore" is a perfectly acceptable reason), I'll keep asking him out.

But that means it's NOT really working--if it was really working, you wouldn't be more interested in the other person.

Some might disagree.

(I have no personal experience with this one way or the other.)