Putting a Bolder Face on Google – A designer, Jamie Divine, had picked out a blue that everyone on his team liked. But a product manager tested a different color with users and found they were more likely to click on the toolbar if it was painted a greener shade.

As trivial as color choices might seem, clicks are a key part of Google’s revenue stream, and anything that enhances clicks means more money. Mr. Divine’s team resisted the greener hue, so Ms. Mayer split the difference by choosing a shade halfway between those of the two camps.