In that situation, the intern should be working for free (for the experience) and the company should consider any actual output to be compensation for the time spent having to help the intern along.
As the post's author noted, the 2 job descriptions he linked to do not fit the above criteria.
Any company that expects actual productivity from an intern is in the wrong.
Maybe we just had unusually good interns, though (this was in the Netherlands).
Complicated tasks need guidance and take time. But they're great for experience.
It's not even that they're really hard tasks, but that there are so many little details to software develop that everyone treats like common sense, but it's not... Until you have experience.
[1] To be fair, one was putting my sample code in production.
Utter bullshit.