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I’ve been using Disqus‘ commenting system on half a dozen websites for quite a while now and I couldn’t be happier with their service. With over 500 million unique visitors per month according to this NYT article, Disqus is a very big fish in the blog plugin pond. But if you haven’t installed this commenting platform on your website, let me give you give you five great reasons why you might want to use this awesome free comment system on your site.

1. Lets your users comments however they want. Facebook? Twitter? Google Account? Open Id? Yahoo? Just your email and name? (What I like to think of as the “we don’t need no stinking login” option. ;-)) No matter how you prefer to comment, Disqus has you covered. You can even create a Disqus account and use that to comment across multiple sites. I love this because it truly welcomes all readers to leave a comment no matter what outside services they use.
2. Encourages sharing. Gives users the option to share or tweet their reply to the post with a single checkbox making them more likely to not just reply but to share their reply with their networks. The Reactions section also highlights users that have retweeted your content which is another incentive to retweet or otherwise share your links on Twitter.
3. Lets you take your commenting identity on the go. Regardless of which login you use, Disqus lets you take your commenting identity with you to any other site that uses Disqus, even if they install it and import your comments in long after you posted it. This lets you track replies and likes but also lets people who are interested in what you said learn more about the other sites you frequently read and comment on. You can always claim older comments after the fact as well so, if you’ve used multiple logins in the past, it’s nice to consolidate. (For an example, see my Disqus profile here.)
4. Works just about everywhere! Tumblr, WordPress,Blogger, TypePad, and just about every major blog platform not only works with Disqus, install is a snap. There’s even a universal code option to easily enable you to add it to any website.
5. Doesn’t hold your comments hostage. Unlike some other commenting plugins out there, if you later decide to uninstall Disqus, it’s easy to export all your comments back into your native comment system. When comments are often such an important part of your blog’s content, this is a very important feature.

Have you used the Disqus plugin either as someone leaving a comment or as a publisher? How did you find their service?