Primary Blogs
The primary blog is the first blog on your account, created when you sign up for Tumblr. This blog has full usage of Tumblr's social features, including following blogs, liking posts, sending asks or submissions to other blogs.
Secondary Blogs
In addition to the primary blog, you can create secondary blogs on your account. Tumblr allows you to create up to ten secondary blogs per day. Secondary blogs lack some of the social features used by primary blogs: they are unable to like posts, follow other blogs, or send asks or submissions. However, secondary blogs can be password-protected, requiring a password to view the blog. You can add other Tumblr users to a secondary blog to create a group blog.
Differences
Primary blogs can:
- Reblog posts
- Follow other blogs
- Initiate social features (like posts, send asks or messages, and submit posts)
- Receive social features (be followed, receive asks and submissions)
Secondary blogs can:
- Reblog posts
- Be password protected
- Have multiple users
- Receive social features (be followed, receive asks and submissions)
Changing Blogs
Secondary blogs cannot be swapped for the primary blog on your account, but you can change the URL for each blog. If you want to move a URL from one blog to another, you can do so by (1) changing the URL of the existing blog to something new so the URL is freed, then (2) changing the URL of a different blog to the freed URL, or creating an entirely new account with the freed URL.