the tweet came a few hours after CNBC leaked it, what I had posted on HN was the original article, it was changed with the tweet after the fact by some mod here.
My comment dates from when we didn't have a tweet or any info, no one knew who the next ceo of twitter was, simply the rumour (not even confirmed news) that jack had left. no one knew, Twitter PR was refusing reporter questions and NYSE had to stop trading until the situation settled
Sending a tweet works just as well to get the message out.