I _am_ red/green color-blind, and I can basically agree with this: If you have to use colour as a signal, use another one as a failsafe -- use different patter

I _am_ red/green color-blind, and I can basically agree with this: If you have to use colour as a signal, use another one as a failsafe -- use different patterns, borders or underlines in addition to different-coloured fills, outlines and texts. But I really want to filter it down to this: When designing your site, use BOTH colors AND symbols/icons to get meaning across to your users. It will be much more intuitive for the average user and will be good enough for me and most people with some sort of color-blindness. I can't expect designers to go out of their way to figure out what colors I can/can't see and which melt in to each other, but I can make the argument above that will help ALL of their users, and me as well.