Color plays an important role in web design and first impressions of a website. It can set the level of professionalism and impact whether a site is taken seriously. There are different color models like RGB and HEX that allow designers to specify colors numerically. Choosing the right colors and color schemes is important, as certain color combinations like complementary colors can increase visibility and readability. Examples of both good and bad uses of color on websites are provided to illustrate best practices.