The year is 2016 and that generation has all grown up now. Back in 1997, when it all started, they were just kids, wide-eyed, impressionable, and truculent at bedtimes. Now? Well, university is done, gap years have come and gone, and separate paths have been trodden; some are lawyers, some dentists, some made it in the new convergence industries, others are content just to make a home.
They are still connected, though, in a weird kind of way, still itching with an almost furtive desire to exchange the House news, share those Hogwarts rituals, turn up at Quidditch events and remain part of all things Potter.
Welcome to the world of brand communities, where like-minded souls converge around a symbolic nucleus that just happens to be a brand. Harry Potter isn't the first content brand to inspire this willing cohesion. 'Trekkies' got there decades ago. The Potter community spirit, though, is being encouraged with unusual zeal by its figurehead, JK Rowling.
Sensing the need of a cohort that grew up with her stories to remain connected, both to her fantasy world and to each other, she has announced that her website, Pottermore, will go live in October, with the aim of keeping fans involved long into the future (see 30 seconds, below).
Not that brand communities are confined to the digital realm. The concept itself predates mass digital connectivity, with its roots in the 1995 ethnographic study by Schouten and McAlexander on the Harley-Davidson subculture. The authors showed that the Harley sense of bonding bordered on the religious, with identifiable rituals and powerful icons.
In 2001, Muniz and O'Guinn followed up with a study on the Ford Bronco, Macintosh and Saab communities, and showed that they displayed a 'shared consciousness' and even a 'sense of moral responsibility'.
With brands today openly seeking consumer interaction, lines are becoming more blurred and a true brand community more difficult to determine. The simplest answer may be that you know one when you see one.
As an analogy, the brand that finds itself at the very centre of a self-forming community is like the pop song that finds itself taken up as an anthem. The transition is one from mere popularity to being seized upon as the totemic representation of ideals, context and time. This is one occasion when the brand very much becomes 'ours'.
Just as songwriters would love to create an anthem, but can rarely conjure one up to order, so brand owners can never be sure that theirs has what it takes to become the heart of a global group.
The most fundamental advice is also the least useful, rather like being told to have good genes to stay healthy: category helps. It's hard to see communities forming around, say, marga- rine; they more typically converge around technology, cars, alcohol, fashion and content.
Beyond that, academics have cited three crucial factors that unite these 'anthemic' brands: an inspiring 'creation myth', the presence of consumption milestones and a practical need for member collaboration.
As with so much in marketing, building a brand community comes down to a fair bit of luck and a great deal of work. If only you could just wave a magic wand.
Helen Edwards, PPA Columnist of the Year (Business Media), has a PhD in marketing, an MBA from London Business School and is a partner at Passionbrand, where she works with some of the world's biggest advertisers
30 SECONDS ON ... POTTERMORE
With the launch of her Pottermore website, JK Rowling is not only giving the existing offline community ways to build social engagement, but is ensuring that the commercial value of the brand remains healthy, too.
- According to Rowling, Pottermore will be 'the place where fans of any age can share, participate in and rediscover the Harry Potter stories.' - A lucky few were able to join on 31 July, Harry Potter's birthday, to help shape the website before it opens to all in October.
- Users will be able to 'journey through Hogwarts', choose a wand and be allocated to one of the Houses by The Sorting Hat. They can also find out what their friends are doing on the site and arrange to meet up with them.
- Aside from being a platform to sell ebooks of the novels, it will also be a place for Rowling to release more information about the series. It's reported that she has already written more than 18,000 words of fresh material for Pottermore.