WordPress.org

Viewed posts are always tracked as long as the plugin is active and the visitor has enabled the cookies.

Download and unzip the plugin file. Upload lastviewedposts.php to your /wp-content/plugins/ directory. Go to the admin backend and activate the plugin.

To display the list, you can use the widget that comes with the plugin or use the following code and place it anywhere you want to, but outside the loop, e.g. sidebar.php :

The single template tag is shown below, but I recommend to use the code shown above. It prevents you from displaying a blank list if the visitor has cookies disabled or did not view any single post yet.

By default the cookie expires after 360 days, the number of entries that are displayed is 10 and pages are recognized.
To change these values, edit the lastviewedposts.php between the equals sign and the semicolon:

$zgcookieexpire = 360; // After how many days should the cookie expire? Default is 360.
$zgnumberofposts = 10; // How many posts should be displayed in the list? Default is 10.
$zgrecognize_pages = true; // Should pages to be recognized and listed? Default is true.