I was under the impression it was minutes? I wouldn't know though, I've never used it. I HAVE to have a hard ticket as a souvenier.
Anyway though, their promotions for it on the back of some of their old tickets say:
1:10 PM Ordered Tickets
1:12 PM Took a Bite
1:15 PM Tickets delivered via email
So they lead you to believe it will be just a few minutes, but the fine print says, "Actual times may vary." So who knows? Could be sometime next week.
This is probably cliche by now, but ticketmaster sucks.