The SoundCloud Ruby SDK by SoundCloud offers methods to handle authorization and execute HTTP calls. Examples demonstrate how to print links of the 10 hottest tracks, work with OAuth2, initialize a client, and add a track to a playlist.
Step back almost 20 years. I was then CEO of a tiny publishing house at a group breakfast during what was then called the American Booksellers Association convention. The guest speaker was a guy with a clearly nutty idea: Jeff Bezos was selling books over the Internet. Every publisher in the room had the same question: who in their right mind would ever buy a book that you couldn't hold in your hands before paying for it?