As a background, it makes online reading difficult because of eyestrain. Black would not be a color for a children's bookstore because of the formality involved with it. Brown is conservative and stable. It is great to use to back photographs. Accent colors that work best are blue, green, red and orange.
Alone brown is drab and boring, but with colors it provides a comfort level that is simple.
Financial sites are backed by a strong green. It is associated with healing, food, ecology, and growth. Although it has quite a few encouraging factors, some also associate it with envy, reptiles, insects, and bodily functions. Use green cautiously. It is best used as an accent color.