9hdigital

This plugin will allow users to chat with the website’s business in real-time by using Facebook Messenger. Users can start a conversation on the website and continue it on other devices at any time.
Please note, Facebook is still currently developing their Customer Chat and so it is still in beta.

WP Chat

Chat with business customers on your website using Facebook Messenger

gpenverne

BlogBuzzTime displays a widget in your sidebar with current readers on your blog.
This is REAL TIME: each time an user leave, or user comes on an article, all your readers will see updated counter.
This plugin provides 2 widgets:
<ul>
<li>
1 showing how many users are online on your blog
</li>
<li>
1 showing current readers
</li>
</ul>
BlogBuzzTime vous permet d’afficher les articles en cours de lecture sur votre blog, en temps réel, ainsi que le nombre total d’internautes en ligne.

BlogBuzzTime for WP

Very nice plugin

BlogBuzzTime displays current readers on your blog, in real time, to other readers. Affiche les articles en cours de lecture sur votre blog, en temps …

WP Chat vs BlogBuzzTime for WP