It is just people ordained by the internet, the law states anyone who does not have a congregation, so my parents were married by a recently graduated seminary student and there marriage is not valid. My friend from high school got married by her retired grandfather, also not valid.
In Rhode Island (and possibly other, or even all, states) you can get a decree by the state legislature allowing you to perform a marriage. I'm fairly sure it's free. My friend had her father get one so he could perform her marriage. What it says is that you're given permission to marry only those two people, only on a specific date and only at a specific locale. So it's not as though you can go around marrying people willy-nilly! Oh, and my friend's father got a cool official-looking document to remember the day.
If people are looking for an alternative to internet-ordained minister, it's something to check out. Call your Secretary of State and see if it's an option in your state.