What is the difference between Public and Private opportunities?

What is the difference between Public and Private opportunities?

Public:
The opportunity will be published to the Opportunity Board and viewable on the organization's profile for anyone to see. Volunteers do not need to be Vome Users to view the opportunity details, but must register a profile to submit an application.
This option is optimal for organizations that are seeking to recruit new volunteers for their opportunities.

Private:
Anyone with the link (URL) can view this opportunity, but it will not be published on the Opportunity Board or on the organization's profile.
This option is optimal for organizations that are seeking to share their available opportunities with their current volunteer base.