Differential pricing is a retail strategy that predates the Internet. If you want to be one of the first people to read a new book by an author you like, you have to spend to get it in hardcover; if you don’t like the hardcover price, wait a year and then buy it in paperback. You can watch a new movie in the theaters, or wait to pick it up on DVD. Pay sticker price for whatever groceries you want, or make the effort to collect coupons and buy the things that are on sale. Etc., etc. It’s all artificial scarcity, in the sense that nothing prevented a publisher from putting out a book only in paperback from day one.

“Exclusive content” is the same idea: the only difference is that the discounted price is zero.