Marko Saric wrote down a few reasons, why you should remove Disqus from your website:
Embedding Disqus makes your site slow Disqus tracks your visitors and shows ads Disqus inserts its own affiliate links in comments and content (for example when you mention Amazon, it inserts an affiliate link to Amazon, to get a referral fee with every purchase) It’s not possible to entirely disable advertising without paying for the premium plan of $10/month, but there are some settings that can make things a bit better.
When you publish websites, write blog posts and make them available on the internet, it’s not uncommon, that you also want to get statistics about how many people read your stuff, how many people visit your website etc. And you also want to enable comments under your blog posts, giving people an opurtunity to ask questions or just leave a reply.
For the first case Google Analytics is the most widely used solution.