Okay, I think I know what the purpose is, but I'm going to ask anyway.
At ORD, the ATIS says (in your best Perfect Paul voice), "When ready to taxi, contact ground metering on frequency 121.675..."
What exactly does ground metering do? I'm thinking they retrieve release times and then get everybody in a sequence and then ground control will just issue the taxi assignments. Is that close?
What exactly do they do that ground control can't?