What I'm missing is;
Which exchange is green and which exchange is the red one?

I tried to choose the colors according to the website theme:
green ... DGEX (like the shadow of the old dgex logo)
orange ... Bter (Bter logo is orange)
blue ... NxtChg (website is styled blue)
gray ... Vircurex (webiste is mostly black and gray)
But basically you are right ... I'll add a better identification soon.