You don't need to register, you already have an account under "Willease" - it works on the main site too
It is not a new feature, though I am now expanding it to offer people like yourself, a way to add case files, and gain exposure for your work. The Message Forums are great (as you can see the traffic this thread gets) but, the majority of my daily visitors never really come here. They mostly hit the FOIA Archive of the documents, and to my surprise, the Case File database is not far behind. Meaning, there is probably more traffic there.
I then take the good ones I post, or that are submitted, and send them to my social network contacts - and they get quite a bit of exposure there, too