Everlane soared to sartorial success with its offering of clothing that's as premium as it is ethical, and has continued to soar with product launches racking up waitlists in the thousands. Now, it's tapping its stylishly-attired community with a private Instagram account.

Girls’ Night in is a members-only Facebook group for LA’s hottest and coolest women, who whisper and giggle between themselves. And while its ranks are small by internet metrics, these women are highly engaged. So what’s got them sharing their deepest secrets with 1,500 friends they’ve never met?

As people spend less time in traditional communities, they’re seeking connections beyond religion and family. Memberships with organisations or brands can create loyalty and boost revenues, but the reasons to join Scientology or Sainsbury’s are vastly different. So why do people become members?

With so many fashion labels having a presence on Instagram – by 2017, over 70% of brands will be on the platform – it's the perfect source for sartorial inspiration. And it is now making it easier to shop on social media, removing the need to interrupt your scrolling with a browser window.