Facebook adds views when sharing a post on the WordPress.com Personal plan

### Impacted plugin

Jetpack

### Quick summary

When a user shares a post to Facebook, even if the Facebook post containing the share is private, Jetpack adds visits and views to the post. I was able to replicate this issue on the Personal plan.

### Steps to reproduce

1. Publish a post. Make sure it's set to post only, so no email notifications are triggered.
2. Share the post on Facebook. Set the Facebook post privacy to "Only me".
3. Go back to the site. Give it some time for the stats to update.
4. Check the stats for the post and Facebook referrers.

### Site owner impact

Fewer than 20% of the total website/platform users

### Severity

Minor

### What other impact(s) does this issue have?

No revenue impact

### If a workaround is available, please outline it here.

Context: 9466735-zd-a8c

### Platform (Simple and/or Atomic)

Simple

Start by reproducing the issue on a WordPress.com Simple site using the Jetpack plugin and a Facebook post set to “Only me.” Trace the stats and Facebook referrer handling to identify why the private share is counted; done means the private share no longer adds visits, views, or Facebook referrers.

Written by the indexing model from the issue text.