Script Summary: Adds a line between old and new tweets as it was in the old design
In the new Tiwtter desgin (December 2011) the line between old and new tweets in the timeline is missing.
You are also annoyed that you have to reread part of your timeline only to find out which posts are new after loading new tweets? This script adds the line between the last new tweet and the old tweets, that was there in the old design.
Small technical detail:
It's a single missing CSS-definition, the CSS-class is already there...