oh, that's a very good point. thanks. first thought is that relying less on variations in hue and using more variations in intensity would help. hmmm. going to experiment. thanks again.
There are different types of colorblindness. The worst being the one where you are totally unable to discern colors. Hue and Value alone won't solve the problem.
For example, at first I didn't see the difference between "Alice" and "Bob" on your about page. I had to look closely to see it. And I'm only mildly color-blind.
For everyone else: there's a color model that is occasionally used in computer vision called Hue Saturation Intensity, which pretty much describes the theory of color that andrewcooke and bornon5 are talking about.
While I have never fooled around with it, I think using the LAB colorspace could be interesting as well. As I remember from my psy course, the two most common forms of colorblindness are red/green and yellow/blue.
Given that the LAB colorspace models these exact axes, it could be interesting for something like this.
But as I said, I have not yet investigated a lot in this direction.