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Provide distinctive red coloring for visited links on all sites.
An alternate style Red: Mark visited links as read on unruly domains (16842) limits the change to a few commonly used domains that do not provide adequate color changes between visited and unvisited links such as Google, and some of the Mozilla and MozillaZine sites.
For some additional effects involving red dashed outline around links when hovering, green dashed borders around no-follow links, and cross-hair cursor for links that open in a new tab/window see No Follow links, mouseover id of other links (DM*) (10987).
Have simply incorporated "red:" bookmarklet as a style. The bookmarklet version can be obtained
at http://www.mvps.org/dmcritchie/lessons/intro/k.html look for "red: Visited links to RED for visibility" and give the bookmarklet a keyword of "red:". The bookmarklet can be used on site for a temporary change instead of using a style.
An alternative suggested by Bob Jamison would be to show a red Unicode character to the left of a visited link so as not to disrupt the author's choice of page colors, though I would find this alternative very distracting, some may prefer it to forcing visited link color, or in addition to changing link color, The 00A0 is a required blank character (in hex), the 141D if available is two small circles at an angle, though his suggestion was 2297. If you don't want to change the link color of the symbol then leave out the "color:red !important;".
a:visited:before {content:"\141D\00A0"; color: red !important;}
It is possible to change the color for links when printed, so they would appear more uniform, particularly when printing with black ink only. Would be nice if Print Preview could be optioned to show how print with black ink only would appear, and of course be able to preview a selection [bug: 140718]. A change such as the following would only affect printing.
@media print {a {color:black;} }
Updates: since 2009-04-27
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