I really have no idea
Here’s the description of the API from delete.im:
Everything we upload to the internet is annoyingly permanent and your users are very aware of this. By using our API you can generate your own delete.im links and make sure their content doesn’t end up where it shouldn’t. Whether you want to use it to send out new passwords or let your users create their own deleteable messages, delete.im makes sure that their data does not hang about.
I could see the API being used to create Snapchat-like services, only, for text. All of the potential use-cases are fairly similar, is would seem. I suppose it could be a simple app made just for showcasing the design, because it is a very nice looking site.
However, I doubt someone would do all this just to showcase a design. I’m sure someone more creative than I can come up with a way to monetize such a thing.
As of this post, I haven’t read the full comments thread on Designer News.