penders - 11:07 pm on Jul 27, 2006 (gmt 0)

I think it is certainly useful when visited links change in some way - it helps my memory too. It seems to be generally accepted that they just change colour in some way, and to be honest if they changed much more than that it could be confusing for most users these days I think.

It is also handy, when you are coming back to a site many days later and you want to find the info you were looking at when you were last there - if the visited links are highlighted then they can point you back in the right direction.

I don't think that main navigation links need to change after they have been visited, as it is likely people will be going back to them again anyway.

It is also useful when a page is linked to more than once from a page, but perhaps with different linking text. After you have visited the linked page, then all the other links change too so you know they are the same and you don't have to bother clicking to see.

ASIDE: Normal links... There are a lot of links out there where the developer has gotten rid of the underline and relied solely on a colour difference to indicate a link - I think this could be problematic in terms of accessibility.