Riveted

While Google Analytics can calculate this metric by default, Riveted features a finely tuned solution that does this at a much greater accuracy.

This is done by detecting and sniffing for user interactions like mouse movements, clicks, scrolling, etc., and recording how much time the user actually interacts with the site, not how much time he leaves the site opened in his browser (while cooking dinner :) ).

Riveted works by pinging site-connected users every 5 seconds and recording how much actual time a user spends on the site.

This 5 seconds period can be changed to any interval, along with the idle period value after which each user is considered inactive and ignored.

Riveted works with Universal Analytics, Classic Google Analytics, and Google Tag Manager.

WordPress Plugin Installation:

Unpack and upload it to the /wp-content/plugins/ directory.
Activate the plugin through the 'Plugins' menu in WordPress.

What is new in this release:

• Added option to use a custom GA global object name.

What is new in version 0.5.0:

• Added option to use a custom GA global object name.

What is new in version 0.3.2:

• Fixed Google Tag Manager label.

What is new in version 0.3.1:

• Fixed IE8 bug.

What is new in version 0.3:

• Added WordPress plugin.

Requirements:

• JavaScript enabled on client side
• WordPress 2.7 or higher (for WordPress version only)
• Google Analytics account