Back in the day when people had 8-bit monitors that only displayed 256 different colors at one time, the web-safe colors were born based on the selected palettes of long-gone browsers. 40 of the 256 colors were displayed inconsistently on Macs and PCs, and thus the remaining 216 colors came to be known as the "web-safe" colors, a set of colors that could be counted on to not dither. This palette is based on math, not beauty, and given that personal computers nowadays typically have at least 16-bit color and usually 24-bit TrueColor, there is little need to restrict yourself to it's limitations.
If you would like to cater to the 16-bit crowd which covers pretty much everybody, then the web-smart colors are the way to go as it only takes 12-bits to display 4,096 colors. The web-smart colors come from the same concept as the web-safe colors, but instead of using only 6 shades of red, green, and blue using the identical hexadecimal pairs of 00, 33, 66, 99, CC, and FF, all 16 shades of RGB hexadecimal pairs from 0-9 and A-F are used.
There are 256 values of red, green and blue from 0 (hex 00) to 255 (hex FF) giving us 16,777,216 colors to play with, and a 24-bit TrueColor monitor will display all that. So now that you know what you are doing and that what you see isn't necessarily what everyone gets, you can use our HTML Color Wheel Coordinator to design the perfect color schemes for your viewers.