They are just an auto insurance salvage pool. Laws vary from state to state about who can enter and bid. It some states anybody can attend and in some states you have to have a salvage or dismantelers permit.

I know a fellow who owned a wrecking yard and he bought there all the time for his yard. But he never bid online; he always went to the auction in person so he could look at the cars up close and see if they were something he could sell.