To demonstrate this, I inspected the source to get the hex codes for the colors. The visited link is #114475, and the plain text is #3b4045. If you run a contrast on these two colors you get a contrast difference of 1.05:1, which would fail WCAG 2.0 AA and AAA requirements if they were foreground and background colors for both normal and large text. WCAG 2.0 AA and AAA requirements can be seen here, and you can also test color contrasts there as well. This is a contrast test run on the two colors.
So, if you can barely tell what the difference is when it is foreground/background colors, I'm not sure how we are supposed to tell when it is two different texts next to each other. I think something like this would be much better, though the color (#7b14cf) could be different.