How do day laborers work? [View all]

[Prism]

I'm ignorant of this facet of our economy, so I was hoping there might be some DUers who could be able to fill in this blank.

Everyday, I drive past a Home Depot where anywhere from 20-60 workers are hanging out on the sidewalk. They have different manners of dress, from labor-related tasks to more professional looking clothes. They're almost universally Latino, which I note because this particular part of the Bay Area is very racially diverse. They're invariably sipping coffee, talking, hanging around with bag lunches, a community of people who seem to generally know each other.

My questions are:

Who's hiring them?
Are they in the system? (i.e. is this labor taxed, are they paying into SS, etc.)
Is this largely lawful business, or is there an undocumented immigrant angle?
What is the pay? Do they typically make enough to support their families?

I ask only because I saw them again Thanksgiving morning and thought, "Who's doing day labor today? And is their economic situation so desperate that they're hoping even for the scant jobs that will be available on a holiday?"

I know almost nothing about how this works, but seeing the workers has always made me curious. So I'd be grateful if anyone could shed some light on it with their own experiences.