How to Keep Track of Followers on Tumblrby David Nield
Like followers on Twitter or Instagram, your Tumblr followers see your updates when they log into the network. Your own dashboard shows how many followers your blog has and how many other blogs you're following yourself; by clicking on either of these links you can see individual usernames and blogs. Recent new followers you've acquired are shown on your blog's Activity screen, which can also be accessed from the dashboard.
Log in to Tumblr and click the "Activity" link to see recent notifications relating to your blog. Among the notifications you will see recent new followers of your blog -- click the plus icons to follow these users back in return.
Click the "Followers" link on the dashboard to see a list of all your blog's followers, with the most recent at the top. Use the search box at the top of the list to look for particular users.
Select "Follow" next to any of the users listed to follow that user back in return. You can also click "Ignore" to block a user or click a username to visit the user's Tumblr blog.