Your personal Tumblr library awaits
Yes, this is real, it works, I was brave and tried it. 
my friend just told me that there's a secret second dashboard that solely contains posts from people you've turned on post notifications for, and when i click the link in the messages it opens it within the tumblr app, so the tumblr app also has a secret second dashboard for post notification blogs, and the only way to access it is to open the link for it within the app.
i literally love tumblr