It looks nice. One supplies an URL and/or a unique identifier of the post to Disqus's JavaScript by putting them in the global space and it will fetch from your Disqus site the comments that are associated with the URL/identifier. Then it will display the comments on the page.

However it looks very nasty that it downloads loads of seemingly unrelated extra stuff. Thus we have removed Disqus from our site. Let's keep our site small and simple. (Nah, seriously, you don't want to comment, do you?)

The world has too much tracking and monetising.