Perhaps people will learn not to trust instant news and a single source. If the White House had been attacked it would have been on all the main TV channels within seconds.
People should treat every day like April 1st and assume a 'breaking' story is nonsense until it gets confirmed.
Obviously, that doesn't happen at the moment and that's why the stock market blipped.
According to the Guardian the Dow recovered in a few minutes so little real harm was done and, if it makes people more wary in the future, it may end up doing some good.