Dark arts in Hollywood - how the publicity smear machine changed

Blake Lively and Justin Baldoni are embroiled in a bitter legal battle over sexual harassment allegations.

The feud has cast spotlight on the publicity machine at work behind the scenes in Hollywood .

Few fallouts have spilled out into the open in recent years and those that did were picked over simply because they're so rare.

But the world of the Hollywood PR has shifted, partly because of the growth of social media.

Social media is a new medium in which PRs can use to shape opinion.

Astroturfing or disguising an orchestrated campaign as a spontaneous up-swelling of public opinion.

This works by manipulating public opinion and creating a false impression of grassroots support.

But all of this is simply a new platform for an age-old trend that has been going on.

Doreen St Felix , a writer who was previously an editor on Lena Dunham's newsletter, recently wrote in The New Yorker that stories of harassment and abuse now receive a "curdled, cynical, and exhausted reception" Less than a decade after the emergence of the MeToo movement.

Sometimes, however, the best way for publicists to prevent stories being amplified is by bypassing social media.