Tagging Tumblr posts is an excellent way to help people search for posts that interest them. Type a word that describes your post in the post editor before you click "Publish," and Tumblr adds the tag to the post. While your Dashboard doesn't have a button to list the tags of posts you've published, you can use a third-party tool that generates a tag cloud that lists all your Tumblr tags.
Pretty Tag Cloud
Visit the Pretty Tag Cloud Maker for Tumblr website and you can build a tag cloud by entering your Tumblr name in the "Tumblr" text box. Click "New Cloud," and the site builds a tag cloud that shows tags you've added to posts. Click one of the tags to view posts that have those tags. Customize the way the tag cloud looks using the controls in the side panel. Click "Save Cloud" and you can copy the HTML code that creates the tag cloud and paste it into your blog.
Tumblr Tag Cloud Widget
You can also generate a tag cloud using the Tumblr Tag Cloud Widget. Type a Tumblr URL into the "Tumblr Name" text box, press "Enter" and view an example of how your tag cloud will appear. This example does not display all your tags. However, you can copy the code form the "This is Your Code" text box and paste it into your blog to put a tag cloud there. Use the controls on the Tumblr Tag Cloud Widget page to customize your tag cloud.
Tumblr Tag Cloud Generator
The Tumblr Tag Cloud Generator does not have many customization options, but you can use the site to create a tag cloud. Type your Tumblr URL in the "URL:http" text box, click "Create Tags" and copy the HTML code from the "Copy the HTML Tags" text box. If you'd like to set the tag cloud's width and height, replace the default values in the "Width" and "Height" text boxes.
Share Your Tags
If you'd like to display your Tumblr tags in your blog's side panel, click the "Customize" button on your Dashboard to view the Customize Themes page. You can paste the code that your tag cloud generated into the Description box in the page's left panel. All Tumblr tag cloud generators don't create HTML code for you, so look for one that does if you want to put your tag cloud in your blog.