Jetpack Comments replaces your default comment form with a new comment system that has integrated social media login options.
We’re breaking down the barriers between you and your audience. When someone reads an article on your site and wants to comment, they can now use one of their existing social networking accounts to post a comment. No longer do they need to create yet another account and profile!
Since it will replace the default WordPress comment form, Jetpack Comments are opt-in. To activate it, just visit Jetpack → Settings on your Dashboard and click the Activate button next to the Comments module.
When activated, Jetpack Comments takes the place of your theme’s comment form in this nifty, sleek form:
To leave a comment, just click in the box and start typing.
After a visitor has written a comment, they will have several ways to identify themselves. A visitor can leave a comment¹ as a guest, or they can choose to use their WordPress.com, Twitter, Google+, or Facebook account. For example:
You can also change the “Leave a Reply” heading and the color scheme of the Jetpack Comments form under the Jetpack → Settings → Discussion tab.
See our Troubleshooting Jetpack Comments page for some help.
¹ If you have “Users must be registered and logged in to comment” enabled in Settings -> Discussion, you will not be able to use the Jetpack Comment form.