In what is ostensibly an effort to prevent exploitation, the government has legally created a situation where an internship is almost completely worthless to the intern.
Whether or not the laws are actually followed in most large businesses, I don't know. However, in the United States there are laws preventing interns from displacing paid employees and doing substantive work.
http://wdr.doleta.gov/directives/attach/TEGL/TEGL12-09acc.pd...
Because of this, I think all "interns" should get minimum wage to work around this nonsensical legal situation and actually be able to legally get in a position to work on something meaningful and to hopefully learn something useful.