If someone is suppressed in my Klaviyo list, will this person still sync to my Facebook Custom Audience?
Yes. If a person is suppressed in a Klaviyo list or segment and you sync this list or segment to a custom audience, the person will still sync to your Facebook audience. If someone is synced to a custom audience through Klaviyo, and then becomes suppressed in Klaviyo, this person will not be removed from your audience. While individuals may opt-out from email communications, you can still strategically reach these customers or subscribers through Facebook advertising.