Internships: Does Unpaid = Unwanted?

A 2012 NACE report on recent college graduates indicates that 60% of students that graduated with at least one paid internship obtained a job offer after graduation:

Paid interns spend much of their time engaged in ‘real’ work; employers prize that kind of hands-on experience. Conversely, unpaid interns spend more time on clerical tasks and less on the type of duties that employers value.

Only 37% of those with unpaid internships received job offers – slightly better than those who didn’t complete an internship (36%)  at all.

So are unpaid internships even worth the effort?