So post it as a comment on the other thread. No need to disperse the discussion amongst half a dozen reputable news sources that all cover the same major event (not to mention pollute the front page with multiple repetitions of the same story).
It also means that comments about an event don't get fragmented into multiple threads.
The only reason I can see to post in separate threads is to gather karma, which is a shame as it doesn't benefit the site as a whole.