I looked into this and found out that only OS X' system-font LUCIDA GRANDE has this problem. It uses some very tight kerning/spacing in order to squeeze more onto the screen. Furthermore it completely ignores the "Minimum Font Size" setting (need to logoff for other fonts) of the Font Smoothing setting, but complies to the method being set there (needs a logoff to come into effect).
All other fonts I have seen that come shipped with OS X, Windows (and Microsoft Office) seem to be aligned to full pixels (so I have to disagree with the "NEVER" statement).
My advice to Zeiter is to change the font within Skype and the different LCD font smoothing methods (weak, medium, strong) and also try different color profiles (they affect the colors used by font smoothing for subpixels). Very likely Skype uses so small a kerning/spacing to squeeze more characters into one line so I cannot tell wether it allows you to change its font behavior.
All other fonts I have seen that come shipped with OS X, Windows (and Microsoft Office) seem to be aligned to full pixels (so I have to disagree with the "NEVER" statement).
My advice to Zeiter is to change the font within Skype and the different LCD font smoothing methods (weak, medium, strong) and also try different color profiles (they affect the colors used by font smoothing for subpixels). Very likely Skype uses so small a kerning/spacing to squeeze more characters into one line so I cannot tell wether it allows you to change its font behavior.