Goto Jetpack Dashboard, You will see Jetpack Comments.
Cheers now you’re all set, and people can comment on your posts using their social accounts and at the same time having the power of Akismet. And, It has pretty neat design. I like it.
For those tho are having problems of not showing the Jetpack Comment interface on their posts:
1.) Manually edit through FTP or Online File manager of your site. (Most Important: dont edit through wordpress backend)
2.) Go to /wp-content/themes/yourtheme/comments.php
3.) Backup comments.php
4.) Not hard part! You need to find comment <form> and </form> tags, and to select all of the lines between them, including <form> and </form>
For my theme was like this:
<form action=”<?php echo get_option(‘siteurl’); ?>/wp-comments-post.php” method=”post” id=”commentform”> …… </form>
5.) Copy all that lines and save somewere on your system, just in case you wont to return to previous state (And DO NOT forget to backup your site before all of this)
Now delete that lines and replace them with just this one line:
<?php comment_form(); ?>
Now click on update file button and go to your theme and check if is working.
Great you DID IT, you mastered replacing custom commenting form with WordPress default one.
If by any case you mess something, mostly bad selection of <form> </form> you need to return all lines that you saved, or in extreamly bad cases recover your site from backup (don’t be scared this happens only if you play to much with code, and you don’t need it in this case)
PS just one more hint you can choose 3 themes for Jetpack comments go to Dashboard – Settings – Discussions and pick:
Have fun with your new Commenting system!