As part of the Jira -> Bugzilla migration, support was added to enable syncing between Jira (jboss.org) and bugzilla.redhat.com (see bug#727851).  The comment sync feature could prove tremendously useful for keeping comments in sync between internal Red Hat bugzilla products and community-facing bugzilla products.

While the scenario also applies for RHEL->Fedora, the Red Hat CloudForms product has several internal bugzilla products (CloudEngine, SystemEngine) that frequently clone to/from public facing community projects (aeolus, katello/pulp/candlepin).  Any upstream bugs where CDW/errata tracking is required for a release, are cloned against the appropriate internal bugzilla product.  Unfortunately, it's often cumbersome to keep progress between internal and community bugs in sync.  

It would be very useful for RHEL->Fedora, and CloudForms->[aeolus,katello,pulp,candlepin] to allow:

 1) Enable bugzilla.redhat.com as a valid "External Tracker"
 2) Whenever a bug is cloned, automatically add the appropriate external bugzilla.redhat.com tracker (optional)
 3) Allow "Send Changes" support for bugzilla.redhat.com external trackers

This support would provide bug owner the option of enabling comment synchronization between internal and community bugs.