Tumblr started out as a photo-sharing blog rather than a text-centric one. As a result, some features -- such as comments -- aren't part of Tumblr's core configuration. However, Tumblr does support the Disqus plugin, which lets your readers comment from their existing social media accounts. You can enable Disqus via the dashboard on most Tumblr themes, though on older themes you have to edit the theme's HTML code and insert three Disqus-specific code samples in three different places.
Disqus-Enabled Themes
Sign up for a free Disqus account. As part of the account setup, you have to choose a Disqus shortname.
Sign in to your Tumblr account, and then click the "Customize" option.
Look for the "Disqus shortname" textbox in the menu on the left side of the page. If there isn't one, see the next section.
Enter the Disqus shortname you got in Step 1, and then click "Save." Disqus adds a comment section to each post you've made on your Tumblr blog.
Manually Linking Disqus
Sign up for a free Disqus account (link in Resources). Choose a Disqus shortname as part of your account setup, and then follow the on-screen prompts until you see a link for "Manual Instructions" -- click on that link.
Copy the embed code under the Manual Instructions section. Paste it into a text editor, replacing "<example>" with your Disqus shortname.
Sign in to your Tumblr account, and then click the "Customize" option.
Click the "Edit HTML" button to view the HTML code for the Tumblr theme you have installed.
Enter the following code between the "<head>" and "</head>" tags:
<meta name='text:Disqus Shortname' content=''/>
Note that the last two quote marks are two single quote marks, not one double quote mark.
Press "Ctrl-F" to pull up your browser's Find feature, and then search for "{/block:Posts}" (without quotes).
Copy the Disqus code from your text editor. Insert a line after the "{/block:Posts}" tag, and then paste the "embed code" from your text editor. Make sure to replace "<embed>" with the Disqus shortname.
Switch back to the Disqus tab in your browser, copy the "comment link code" in the last step on that page, and then paste it directly above the “{/block:Posts}” tag in your Tumbr theme's HTML.
Click "Update Preview," and then click "Save" to save your changes. On your Tumblr console, select "Appearance," and then enter your Disqus shortname in the space provided.
Disqus-Enabled Themes
Sign up for a free Disqus account. As part of the account setup, you have to choose a Disqus shortname.
Sign in to your Tumblr account, and then click the "Customize" option.
Look for the "Disqus shortname" textbox in the menu on the left side of the page. If there isn't one, see the next section.
Enter the Disqus shortname you got in Step 1, and then click "Save." Disqus adds a comment section to each post you've made on your Tumblr blog.
Manually Linking Disqus
Sign up for a free Disqus account (link in Resources). Choose a Disqus shortname as part of your account setup, and then follow the on-screen prompts until you see a link for "Manual Instructions" -- click on that link.
Copy the embed code under the Manual Instructions section. Paste it into a text editor, replacing "<example>" with your Disqus shortname.
Sign in to your Tumblr account, and then click the "Customize" option.
Click the "Edit HTML" button to view the HTML code for the Tumblr theme you have installed.
Enter the following code between the "<head>" and "</head>" tags:
<meta name='text:Disqus Shortname' content=''/>
Note that the last two quote marks are two single quote marks, not one double quote mark.
Press "Ctrl-F" to pull up your browser's Find feature, and then search for "{/block:Posts}" (without quotes).
Copy the Disqus code from your text editor. Insert a line after the "{/block:Posts}" tag, and then paste the "embed code" from your text editor. Make sure to replace "<embed>" with the Disqus shortname.
Switch back to the Disqus tab in your browser, copy the "comment link code" in the last step on that page, and then paste it directly above the “{/block:Posts}” tag in your Tumbr theme's HTML.
Click "Update Preview," and then click "Save" to save your changes. On your Tumblr console, select "Appearance," and then enter your Disqus shortname in the space provided.