Aritic PinPoint automatically syncs your segments every 6 hours with Facebook Custom Audience
A practical example of this sync:
If you create a Custom Audience Segment at 10 a.m. with a segment of 300 contacts, the Custom Audience will have 300 contacts stored on Facebook.
In the following 6 hours, your segment increase at 350 contacts and Aritic PinPoint, at 4 p.m. will sync the new 50 contacts.
Unsubscribers ARE NOT used into your Custom Audience for privacy and security reason and are removed from the audience as soon as Aritic PinPoint update the audience from its segment.