If you or your organization have a Partnerships contact at Facebook, please reach out to them for full access.
Anyone can immediately access our most popular feature that's publicly available. It's our Link Checker Chrome Extension and you can go here to get it. It makes it really easy to see how often a link has been shared, who shared it and even what they said.
We are working on making more versions of our platform publicly available and will continue to ship those as soon as they are ready!