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

Eero Hermlin

Native, lightweight, super-fast plugin for updating comments in real-time with Ajax, without need to refresh the page. Allows comments section work interactively like a chatroom. Comments re-classified as trash or spam will be dynamically removed from users screen. It’s pure WordPress plugin, no need for third parties (like Disqus), no paid services, no secondary logins. Perfect alternative to Disqus.
Administrator can choose update frequency, define in what pages realtime comments are used, comments ordering in selected pages. Additionally is possible to set custom walker function (if used theme uses it) and size of avatar.
Supports also paginated view of comments: in this case new top-level comments will be dynamically are added to newest comments page. Nested comments will be dynamically added to parent comments at any comments page.

Realtime Comments

Accepted comments from users are added to pages in real-time, without need to refresh. Makes comments section work interactively, like a chatroom.

WP Chat vs Realtime Comments