Disqus is a third party featurefull commenting system for WordPress and other website frameworks. WordPress already provides you a built-in commenting system and it has its own commenting network which anyone can activate with Jetpack by WordPress.com plugin.
Then why use, Disqus? Because it makes things easier for you and your visitors. A lot of popular websites like labnol, CNN, The Next Web, Bloomberg, Sangkrit, CNBC etc use it.
It better controls all spams, it doesn’t turns your page slow if you have lots of comments on your article, provides you easy moderation interface and better subscription options.
To start using ‘Disqus’ comment system on your WordPress site
What you have to do is type in a name-for-your-website.disqus.com in the fields shown in the given screenshot.
After adding your website to Disqus.com, login to your WordPress admin area dashboard and install-activate Disqus Comment System plugin.
Clock ‘Configure’ link below Disqus Comment System plugin on all plugins screen (Plugins-> Installed Plugins) and then follow onscreen install instructions.
Here it will ask you to login to your Disqus account by typing in your Disqus username and password.
Type in your username and password then click next button and it will show you the name of your website you added before. Select your website to finish installation.
You can moderate your website comments from your admin area dashboard Comments -> Disqus screen. Here you can approve, spam, or delete your website comments.