I wonder: does Ticketmaster not make any profit at all on the ticket sale itself (does all that go to the act), and is the "convenience fee" actually their profit? Or is there profit built into the ticket price itself, and the convenience fee just additional profit?

If it's the former, it's still lousy because they're advertising lower prices than what the actual cost is.

But even so, it's still not much different from retail stores charging sales tax. Personally, I think it should be illegal to charge sales tax after-the-fact. The price advertised should be the price you pay, period. In Europe, this is exactly how it is: whatever price you see advertised is what you pay, and that's all. There's taxes (15% VAT I think, so not trivial), but they're built into the price, and they're not allowed to advertise the pre-tax price. This is exactly how it should be.