During my publishing career, I've worked with many interns and have been lucky enough to have belonged to organisations which believed in giving these people genuinely important tasks which both extended their knowledge and skills and allowed them to make real contributions to various publishing programmes. Thanks, at least in part, to this experience, many interns of my acquaintance went on to obtain full-time posts, sometimes within the same organisation, when opportunities developed. I have no moral problems with this practice, as long as it is made absolutely clear what the terms are (i.e. whether travel, lunch or other remuneration will occur) and that there is a genuine commitment to interns' training and development on behalf of their employers. The smug liberal in me, however (which is quite large constituent element) was shocked recently when there developed - certainly in publishing and probably elsewhere - a ferocious moral storm of outrage against this practice, with critics in some quarters equating it with slavery, and at least one major book excoriating the practice in a wider context; Intern Nation.
It's always good, of course, to have one's opinions challenged, if only so that they can be examined afresh and therefore do not become unthought assumptions (they told me so at university, via John Stuart Mill). Having been so invited however, and notwithstanding some of the reasonable arguments that were advanced against internship, I remain convinced that the practice is a morally valid one. Of course there will always be people and companies who abuse the system, but that does not constitute an acceptable condemnation of internship as a whole. Interns can play a vital role in keeping (especially small) publishers viable and connected to new ideas and receive in exchange, and with best practice, real opportunities to develop their experience, skills and network of contacts, all of which makes them more attractive employees.
The Comment button waits quivering for you to convince me otherwise.