I love retweets about blog posts. I don't know about all the blogs out there, and I don't want to read every post.
However, if someone I am following on Twitter retweets a blog post that I find interesting, I will go read it.
Lorna, how about including a simple paragraph at the top of each post asking people that comment via twitter to use hash tags. #lj1234 where 1234 is your post id? And then have a script the searches for those.
Maybe bold ARE YOU TWEETING? USE #lj1234 TO JOIN MY CONVERSATION
Just a thought.