In her work running a day care, Ruth Kaiser is surrounded by smiling faces - and not just on the children. She calls them "Spontaneous Smileys" - things that just happen to look like they're grinning.

The smiley — a circle, two dots, and a curved line — is a time-honored symbol of happiness. Archeologists recently found one on a 3,700-year-old jug, and it made an appearance on a lega… ...