Tumblr won't let you make your entire account private, but you can have private blogs and private blog posts that allow you to share your ideas, pictures and videos with only the people who have your permission. The privacy settings in Tumblr are accessed through the settings and customization tools.

Create a New Private Blog

When logged in to Tumblr, you'll see your Tumblr Dashboard. From there you can click on the name of your primary blog and select "Create a New Blog." There you can enter the details for your new blog and put a check in the box labeled "Password Protect this Blog" in the Privacy section. You'll need to type in a password that will then be the gateway for people to view your private blog. When you're done, click "Create Private Blog" and start posting.

Make a Secondary Blog Private

Even if you already created a secondary blog on your account, you can still make it private after the fact. From your main Tumblr Dashboard, click the down arrow next to the name of your secondary blog, choose "Customize" and then go to the Advanced tab where you can add password protection. You can also use the Advanced tab to de-list your blog from search engines and Tumblr promotions to keep things extra private.

Private Blog Posts

If you don't need an entire blog to be private, but would like to post something that only other administrators on your blog can see, use the Private Post feature. When you're creating a new post, click the down arrow next to the "Publish Now" button. From the options, choose "Create Private Post." Private posts don't require a password to view because they will show up only for people who are administrators on that blog.

Ignoring Users

If it's just a few users that you want to keep from seeing your blog, you can ignore them specifically which will prevent them from seeing or commenting on your blog while they're logged in to Tumblr. Go to the Tumblr Ignore Users form (see link in Resources) and enter the username of the Tumblr user that you want to ignore.