You've got dozens of qualified applicants for your opening, and at this point you're no longer looking for new candidates. But you and your team are still in the throes of the hiring process, and need to be able to work on the opening–reviewing documents, messaging candidates, creating notes, etc. Private openings offer all the same workflow functionality within the ATS software but are not available to the public.
Hidden from Public View
After an opening is designated as private, it will not be shared with the outside world. The opening will not appear on your jobs widget, hosted careers site, external job boards or anywhere else. If you would still like to share the opening with select candidates, you can create a private link to the opening, but it will be otherwise inaccessible.
Narrow Your Focus
Once your candidate gathering is complete, private openings allow you to devote all your focus to the applicants that matter, rather than risk being distracted by applications that pour in well after you need them.