I talked about reseller channels.
A reseller channel doesn't own tickets. It's just a website. I think StubHub would present themselves as a channel, not as a broker. They'll speak eventually, but from my understanding of their business, they are a channel.
A broker is somebody who buys tickets and then might operate a website. I know of sellers who are also brokers in some smaller markets, but those are two different things. One has a financial risk and is probably exceeding the purchase limits when the show goes on sale to get more supply, and the other one is just a channel.