When there is less of anything, we tend to value it more. Scarcity suggests there was once more of something, today there is less of it, and tomorrow it might shrink yet even further. Think of a wholesale store vs. a boutique one and then look at how their pricing often compares. Then think back to the wholesaler and notice one scarcity strategy that they apply nevertheless, in light of having a wider product offering. Some wholesalers or mega retailers will actually do limited products that are only available until they are bought out, without replenishing the supply. In software, we often forget about scarcity because more often than not, bits and bytes can be so easily duplicated and there is so much abundance with the help of copy-paste. Nevertheless, in the world of UI, scarcity can still be used to show limits or bottlenecks that relate to the real world. Think of the limits behind the number of tickets you can sell to a webinar, the number of clients you can service in a month, or the number physical products you might have before the next batch is produced. All these things can be shown to the user to evoke action while being more informed. Think supply and demand. Think less is more.