WikiLeaks is accepting submissions again, after a nearly five-year hiatus. Anyone who wants to submit a document can do so by accessing a new Tor site to anonymously upload whatever scandalous files you've obtained.
Submissions were paused in October 2010 after vicious infighting among staff, as Wired's Andy Greenberg pointed out:
The site's administrators wrestled with disgruntled staff members who had come to see WikiLeaks founder Julian Assange as too irresponsible to protect the group's sources. Defectors from the group seized control of the leak platform, along with thousands of leaked documents. Control of that leak system was never returned to WikiLeaks, and the defectors eventually destroyed the decryption keys to the leaks they'd taken, rendering them useless.
Since the WikiLeaks submission portal shut down, other media outlets have relied on programs like SecureDrop to offer whistleblowers a way to share what they know. Even with this submissions portal re-opened, leaking to other outlets may still be more appealing. WikiLeaks' habit of publishing raw, unvetted files is one of the reasons Edward Snowden chose to contact journalists instead of WikiLeaks.