Are interns mugs?

What is an intern, or an internship? Is it training? Work experience? A student placement? Volunteering?

I’ve been looking at this recently, and I confess to some confusion. Some internships seem to be paid; some not. But where they’re not, is this just a form of exploitation, substituting a free or cheap intern for a fully-salaried employee? Or is it a legitimate way to gain entry to a new organisation or industry?

Wiktionary takes a narrow view. It offers two definitions, the first of “a student who works in order to gain experience in their chosen field” and the second a more specific definition for medical students. Dictionary.com takes a different view: “a person who works as an apprentice or trainee in an occupation or profession to gain practical experience, and sometimes also to satisfy legal or other requirements for being licensed or accepted professionally.” The Oxford English Dictionary goes for “a student or trainee who does a job to gain work experience or for a qualification”.

This question came up, for me, in the context of volunteering. It seems entirely reasonable to me that, just as people give their time freely to public, community or charitable organisations, to make a contribution and/or perhaps to gain useful knowledge or skills, and just as some professionals volunteer their time pro bono, so it may be that those seeking entry to a new career may offer their services free in return for the experience.

This is fine from the volunteer intern’s point of view, but if the organisation uses this as job substitution, perhaps even laying off paid staff to recruit unpaid interns, is this morally acceptable?

My half-formed opinion on this is that we need guidelines. A kind of code on internships. There’s a thorough review of what happens in various countries around the world at Wikipedia. And a provocative discussion forum at interns anonymous.

I’d welcome feedback. Is there a right way and a wrong way to organise and offer internships?