As someone with very mild red-green colorblindness (based on the article, probably protanomaly or deuteranomaly), I'm not really ever affected on the web. However, I HATE it when games (often puzzle games) use red and green color coding. I see them as distinct colors, but for certain shades, the contrast between them is very slight, which makes the game a lot more difficult and frustrating.<p>I guess it's one of those things where if no one on the team suffers from it, they have no real reason to consider it.
Colorblind people are only just one small group that need to be considered. Since not many sites use a blatantly impossible color scheme (truth be told the last time I've been told by a colorblind friend that there was a problem was back when Apple used red and green dots for iPhone availability (2g, not 3g), now Apple's using shapes and colors), I'd say the bigger accessibility travesty I can think of now are sites that use image-based captchas with no alternatives (audio, answer a question, etc.). Grrrr.<p>Not to say I don't think much of colorblindness (I still test for that on the sites I work on, there are some excellent tools around for that purpose), and not to say that I love spam, but I hate those particular types of captchas.