I hate to pour cold water on this, but the tweet wasn't the value here : It was the announcement itself. Making it in the newspaper (as would have been done in the past) would have been just as effective. Or via Bloomberg (on their terminals).

OTOH, adding the detail about talking to the CEO is a little odd : Is the implication that he's trading on information that he got from a private conversation? The whole area is a little murky, I guess, because the intention to buy a block should also be material market-affecting information, but somehow it's not against the rules.