Much like today, the cult and celebrity of the Bright Young People of 1920s London was a creation of the media, who encouraged this predominantly upper-class group to lead increasingly chaotic lifestyles, as Beverly Nichol's remarked, "because we knew they were watching...".
In 1926, newspapers began to recruit members of the Bright Young Things to write the society news and gossip columns for them, and hence the celebrity of the Bright Young Things became self-perpetuating.
Patrick Balfour, who wrote for the Evening Standard and later the Daily Sketch declared "[the gossip column] was an institution in which all parties - host and hostess, partygoer and press cameraman - gamely colluded. People who led public lives were fair game."
It seems in our era of social media and celebrity, nothing has really changed.