Barely heard of in the UK three decades ago, internships have become must-haves on the CV of any young jobseeker. Why?
They are the bright-eyed, smartly-dressed young faces in your office, full of nerves and energy.
If they're lucky, they will get a valuable insight into the world of employment. If they're not, they can look forward to hours spent making tea and photocopying.
The work experience placement has become almost a guaranteed rite of passage in an increasingly competitive job market.
To many employers this is a welcome development, allowing them to screen potential new recruits and ensure that new workers have a basic grasp of workplace dynamics before they clock on for the first time.
But to critics, interns are nothing more than a vast army of unpaid labour - and the expectation in many industries that they will be prepared to work for free means it is largely those from privileged backgrounds who benefit.
Whatever your take, there is little doubt that work experience has an increasingly large impact on what will be the job prospects for many young people.
Some 21.7% of summer 2009 graduates who were in employment six months later had been taken on by an employer with whom they had previously had some kind of work experience, according to the Higher Education Statistics Agency (HESA). For the first time they represented the largest group of university leavers.
As a result, this summer will see many young people taking time out from their studies by making their first excursions into office life - if they calculate the traditional bar, shop or fruit-picking job will not now look impressive enough as they forge their future careers.
But it's not only undergraduates who feel compelled to volunteer their services. Emily Farley, 24, has undertaken six internships at magazines since leaving university with a first-class degree in her bid to break into journalism - and has lined up two more.
All have been unpaid and only a handful have made a contribution towards her £400-a-month travel expenses into London from High Wycombe in Buckinghamshire. Although Emily has supported herself by working between each placement, she has grown increasingly frustrated that work experience is the only route to proper work.
"It seems as though internships have replaced entry-level jobs," she says. "It's all about being in the right place at the right time.
"My family have been very supportive, but sometimes they say, 'do you feel you're getting any closer?' This just seems to be how it works nowadays."
How did work experience come to assume this role, almost analogous to the mediaeval apprentices who would have to shadow a craftsman before being allowed to join a guild?
American author Ross Perlin, who is writing a book on the rise of internships, says the word "intern" was first used in the US to describe junior doctors in the 19th Century. Its name - if not its salary - was adopted in the 1930s by a scheme to provide volunteer work experience with politicians in Washington DC.
"In the 1960s and 70s, when you mentioned an intern people would have thought you meant a medical intern," he says.
"By the 1980s and 1990s many companies saw it as a way of saving on labour costs. Likewise, the not-for-profit sector has been substantially powered in the last couple of decades by the fact that it's able to use intern labour."
Across the Atlantic, the explosion in access to higher education meant that British bosses began looking at similar schemes to distinguish the growing phalanx of undergraduates seeking entry-level positions each year, according to Heather Collier of the National Council for Work Experience (NCWE).
She dates the boom in British internships from 1997, when Lord Dearing's report into higher education called for some form of work experience to be undertaken by each undergraduate.
"A lot of employers were complaining that the graduates they were taking on weren't work-ready," she says. "It was very much seen as a business tool that could help both companies and their future recruits.
"Some people say it's elitist, but it's in the interests of companies to pay their interns They want to take on the best and don't care where they come from. And there are a lot of fantastic internship vacancies every year that go begging."
However, many remain cynical about the motives underlying employers' preference for work experience.
Warwick University's Professor Kate Purcell, an expert in the graduate labour market, says there has been a decline in the number of sandwich courses, in which students, traditionally on vocational courses, get to spend a year in a relevant workplace.
She says with more competition among graduates than ever, employers in all sectors have looked for inspiration to traditionally over-subscribed industries like publishing, politics and the media, which have long expected new entrants to toil for little reward before they break into paid work.
"Employers are remarkably good at complaining about highly educated kids who don't know anything about the real world, but less good at actually getting students in to do structured work experience that actually teaches them something," she says.
"In reality, they're treating internships as a first stage of recruitment, but they aren't doing anything to widen access opportunities. As a result, occupations like journalism are becoming increasingly middle-class professions."
Nonetheless, few would dispute that well-run, properly-structured internships are of immense value to those lucky enough to make the most of them.
Becky Heath of the social enterprise Internocracy believes those doing unpaid work experience are being exploited and should get the national minimum wage, but says it would be wrong to do away with them altogether.
"There are so many advantages to internships, so what we want is to make access as wide as possible.
"It would be tragic to confine these opportunities to those who can afford to do them. At the moment, the whole landscape is so new that it's an entire hidden economy."
With age of the intern still in its early days, pressure may be building from groups like Internocracy to refine and, they hope, improve the system.
In the meantime, spare a thought for the student plonked next to the photocopier. Maybe it's time you offered to get the teas in?