Password Protecting a URL in Tumblrby David Nield
You can set up several blogs associated with your Tumblr account -- the first one you create is known as the primary blog, with any that you create afterwards known as secondary blogs. Among the features available on secondary blogs that can't be used with your primary blog is a password protection option that lets you restrict who can see the content you post.
From the Tumblr dashboard, click the drop-down menu at the top of the sidebar to the right of the recent posts. All of your current blogs are shown, and you can select "Create a New Blog" to start a new one. You can manage your existing blogs by clicking on the Settings icon -- marked with a gray cog symbol -- at the top of the dashboard, to see your current primary and secondary blogs listed on the left. Select any blog to change its settings or to delete it.
Adding Password Protection
When you create a secondary blog, you have the option of password protecting it when you choose a URL and title for the new site. You can also add, remove or modify a password from the Options page, which you can access from the main Settings screen. To modify an existing password, click "Change Password," and then enter the new password in the field provided. Click "Save" to confirm any changes you've made.
How It Works
By password protecting your blog, no one will be able to see it on the Web or follow it on Tumblr without knowing the password. The blog's front page, individual post pages and static pages will all require the correct password in order to be viewed. However, you cannot password protect an individual URL -- such as a single blog post or a single static page -- while leaving the rest of the blog public, which means that your secondary Tumblr blogs must either be entirely public or entirely password-protected. You can create individual private posts on any Tumblr blog, but these are not password-protected -- they are kept private so that only the blog admins and members can see them.
Adding a password to one of your secondary blogs means that you can keep tabs on the number of people who are able to access it -- it works well for situations where you want to keep a blog private between a small number of people. Posts created on a password-protected blog cannot be reblogged by other users, and any tags used on these posts won't show up in Tumblr searches. Of course there's nothing to stop users with access from copying and pasting content such as images elsewhere on the Web, so be careful when choosing who you give out the password to.