If I visited a question before, it would be helpful to display a hint showing when the page was last visited.
Right now the link is highlighted with a different color, but only if I'm visiting from the same browser & PC. So this is standard functionality of a browser, not something coming from Stackoverflow.
I suggest replacing this:
Then I can see this information when accessing SO from different devices. I believe it should help improve site navigation - avoid round-trip to questions that users have already visited and acted upon.
An extension to this idea is to include total number of visits by YOU:
If no visits were made yet, it should look the same as now (screenshot #1 from the above).