Genuine Smiles.

The BBC has an online test to see if you can distinguish between fake and genuine smiles. You've probably all read about this already -- spontaneous, genuine smiles activate different facial muscles than forced ones (unless you train yourself). In particular, the skin under the eyes wrinkles in a genuine smile.

Knowing this, consider the expressive power of these two ASCII smilies:

:)

^_^

The first is the standard Western smiley, and the second is the one I seem to see people from East Asia using more often. To me, the second looks much more like a real smile, even though there is no actual curve to the mouth. I wonder if the effectiveness of these smilies is subconsciously related to some innate ability to differentiate honest smiles. (Though people are evidently not very good at doing it on actual faces.)