I am using Wordpress 2.9.1. I recently noticed the trackbacks are not being sent - internal or external.
I see two issues I would like to solve.
1) My site has a default, global ping hub which it should notify. This value is not being set into the 'to_ping' value in the *_post table.
2) When I manually enter a trackback in the post, I notice the 'to_ping' value is properly set. It never sends the ping though. The 'pinged' value is always empty.
With older versions of WP, this seemed to work automatically.