Some web authors argue that if a user is on the 'news' page, the 'news' link in the navigation bar should be disabled.
This is usually on the basis that if the user clicks on the link again, they might get confused as to why the same page loaded again... i.e. why did that link do the same thing as last time?
Personally I don't think that users are confused by seeing the same page loading again... instead its usually the navigation bar which has an inadequate way of informing the user what the 'current' page is.
This problem is perhaps most evident by people who are viewing the site page-by-page... if they had an easy way to identify the 'current' link, they can use that as a reference to go-to the neighbour link - i.e. the one visually below it.
Hopefully that explains why I think disabling the link is trying to create a solution, without identifying what the problem really is.
This is fair enough though, as at the end of the day developers are just trying to find a solution... but unfortunately, in this particular case, the proposed solution makes the experience worse... remember the user is lost, disabling a link isn't going to fix it.
The reason I believe it makes the experience worse is because users can get frustrated due to the 'well it worked a minute ago' issue with the links.
One of the situations I see quite regularly is when someone is lost or confused (with anything, even outside of the web), they will repeat an action two or three times to help them understand and remember that if they do that action, it will always have the same result.
This repeating of actions is like (but not the same) as an obsessive compulsive, whereby they may switch a light on and off 3 times to be sure that it really does go off.
And on a personal note, when I am scanning though a website, I sometimes need to re-load a page (possibly due to some JS altering the page content)... I know that I can press the browsers refresh button (or keyboard shortcut), but usually the easiest way is to use the link from the navigation bar, as my mouse is usually hovering over it anyway.
However, if the link gets disabled, then I usually think... if only for a split-second...
Personally I believe a navigation bar shows a fantastic view of the websites structure (if done well)... and if you put in a really obvious 'current' style on one of the links, the user knows exactly where they are within the website... so they should be able to work out for themselves that if they follow the 'current' link, then it will re-show the same page, in the same way that link worked last time.
Really navigation bars need to be as consistent in as many ways as possible... this is because users don't visit websites for the navigation bar, they are there for the content.
Any feedback would be greatly appreciated, I don't include comments due to the admin time required, but if you email me, I will reply and make appropriate updates. Also, if you would like to take a copy of this article, please read the terms this article is released under. This article was originally written Saturday 17th March 2007.