In any web browser, it is easy to see which links have been previously visited by looking at the color of the links. By default, all unvisited hyperlinks are blue in color, unless their colors were altered by a Cascading Style Sheet (CSS), and all visited links appear in the color purple. The colors persist even when you refresh the page, or open the page after several days, as long as the URLs clicked are still available on Firefox history.
Without doubt, this is a privacy breach and can be embarrassing and inappropriate when someone else is using your computer, because your past history is on screen in plain sight, and the user isn’t even checking out your browsing history.
Now it is always possible to use private browsing or delete browsing history after a session. It is also possible to selectively delete URLs and pages from Firefox history, but if you want a quick an easy way, check out this new extension.
Remove Visited Link is a restart-less add-on that lets you easily change a visited link to an unvisited one. Simply right-click on a purple link you want Firefox to forget, and from the context menu click on “Remove this link from history”. Immediately, the link turns blue indicating that it has been successfully removed from history.
The graphic below shows how the add-on works.