So many geniuses in this thread who got a C+ in Econ 101 and think they understand the whole issue.
When you graph employment and wages, there is, indeed, a portion of the population that will be employed at any arbitrarily low wage.
What you aren't graphing is that those people then starve to death.
I'm a medium-strength supporter of student-minimum wages, for part-time student employees. This would let employers fill low-wage jobs with the folks who actually need the jobs for experience at the cost of needing at least two of these employees per FTE position. Realistically, I could see this wage being discounted by up to 25%, and possibly exempt from some social-safety net payments on the employer side. This still distorts the labour market to an extent, but might be a good trade-off.
If you have a business that requires responsible, full time, adult employees, but you need them for $4/hr, then you have a bad business.