It's a place where the submitter of the confession will never be revealed, and you can submit in either the submit box or the ask box. If you want to submit something but you don't have a tumblr, you can go on anonymous and leave a submission in the ask box.
And the blog itself is here if you want to browse the confessions. Here are a few small examples:
Spoiler: show
The link is also in my signature. I forgot it was there .3.