Understanding Palin's Secrecy

A reader writes:

If you think of Palin as a politician trying to build a movement, it's indeed peculiar that she wouldn't want any video or audio coverage of an address that was, reportedly, delivered well and warmly received. But if you think of that address as content she wishes to sell at paid appearances, the restrictions make perfect sense. She wants to be paid to deliver this speech again and again, just as a movie distributor wants to charge numerous audiences to watch its film. If people see it online, they're less likely to pay to see it in person, and there will be some who decide they don't like it enough to pay for it.