I'd like to customize the Publicize messages that get sent to Twitter and Facebook so that each one is different (the Facebook message, for example, would contain more text as it doesn't have the tight character limits that Twitter has).
I found an article called Customizing Publicize Sharing Behavior on vip.wordpress.com that mentions two filters I can attach to:
$status_update = apply_filters( 'publicize_twitter_message', $message, $post, $url );
$status_update = apply_filters( 'publicize_facebook_message', $custom, $post, $url );
However, searching the Jetpack codebase for those filters turns up nothing. Are those filters only available on WordPress.com? And if so, is there any way to accomplish the same thing with the Jetpack plugin?