We understand and appreciate your privacy concerns. For this reason, we'll be modifying the comment cross-posting portion of the Facebook and Twitter Connect feature so only comments on public entries (those marked 'Everyone') can be cross-posted. Once we implement this change, it will no longer be possible to cross-post screened comments or comments left on Friends Only entries.
The full post is here on news.
I personally think this is a good balance but it would have been far better had LJ done this from the start.