Color Symbolism

Colors are an element of design that people react to on a visceral level and often they don't realize it. When choosing the colors for your site, you need to first (as always) think of your audience. Is it a global audience? Are they older? Younger? Male? Female? All of these things can affect the color choices for your site.
Age Differences
Young children tend to prefer brighter, while adults tend to prefer more subdued colors.

Class Differences
Marketing research in the United States has shown that working class people tend to prefer colors that you can name: like blue, red, green, etc. While more highly educated classes tend to prefer colors that are more obscure: like taupe, azure, etc.

Gender Differences
Very often men tend to prefer cooler colors (blues and greens) while women tend to prefer warmer colors (reds and oranges). Western men are often unable to see some of the differences in color on Web pages.

Trends
Colors, like everything else in design, go through ins and outs in popularity. Black Web pages were all the rage a few years ago, and now you hardly see it at all (but it will surely come back). Color usability also changes towards seasonality. In other words, the designs reflect the season they were built in: winter blacks, whites, and greys; spring greens and bright colors; summer yellows; fall browns and golds.