These things are all well and good as visual examples of what the thing is, but pretty bad as logos imho. A logo should be simple, be able to be displayed at a small size, be able to be displayed in two colours (like in a black-ink-only photocopy) all without losing any of the impact. None of these images have any of these qualities, aside from Flame's example. I think you're all trying to cram too much into this; remember, a logo is not a pictogram of the function, it's a simple graphic that is ideally tangentially related to it.
Flame's is by far the best here, as a logo, imho. It's simple, it works in only two colours, can be displayed at any size and it's representitive of the ideal. It could use some more work to be a terrific example, but I think it's going in a pretty great direction right now.
That's just my 2c, of course.