Henry Wright

Here makes use of the WordPress Transients API to keep a record of who’s currently online. A green dot will appear next to each active user.

Here

See who's online now on your WordPress site.

Danny van Kooten

ibericode

Harish Chouhan

This plugin shows your Mailchimp lists activity, right in your WordPress dashboard.
<h4>Mailchimp lists activity</h4>
Once activated, it will show a new dashboard widget containing a bar-graph or line-graph (<a href="https://wordpress.org/plugins/mc4wp-activity/screenshots/">screenshots</a>) showing day-to-day changes to your Mailchimp lists. You can choose to view relative activity (daily subscribes vs. unsubscribes) or a line graph visualizing your total list sizes.
Requirements
This plugin has the following requirements.
<ul>
<li>The <a href="https://wordpress.org/plugins/mailchimp-for-wp/">Mailchimp for WordPress</a> plugin (3.0 or higher).</li>
<li>PHP 5.3 or higher.</li>
</ul>
To get started with the plugin, please have a look at the <a href="https://wordpress.org/plugins/mc4wp-activity/installation/">installation guide</a>.

MC4WP: Mailchimp Activity

Disclaimer: I'm the plugin author.
We've been using this plugin internally for quite a few months now to show MailChimp list sizes right in our WordPress dashboard so we didn't have to log into our MailChimp account every now and then to monitor list related activity. 
So yes, we use it on a daily basis and love it. Now we decided to share it with you, for free. :)



Handy for a quick overview of MailChimp list activity.

Very handy executive summary of your Mailchimp list anayltics right in the dashboard. Thanks!



Featured on iThemes Training Plugin Roundup, March 2016

Shows activity for your Mailchimp lists, right in your WordPress dashboard.

Here vs MC4WP: Mailchimp Activity