P.S. I'm working on a website that will allow people to swap their books. https://www.swapiverse.com/
Other than that, we want to also allow privacy for users. It would cost extra for users, but if they wanted, we want to serve as a midpoint for shipping. You want a book shipped to you, but don't want your address sent to a random person? We will receive the book, and then send it to you.
Finally, we hope to have a larger inventory available. I couldn't find books I actually wanted on pbs.
Past that, and this is way in the future, we plan to expand to anything that is worth trading. Videogames is next on my list, then after that, records. The list is slowly growing, but I think our potential for expansion and scaling is really high.
It's amusement instead of bitterness because we're already, and have always been, profitable doing machine learning projects for large organizations in different sectors and industries and we just happen to be building our machine learning platform to solve real problems we have first hand experience with. I suppose I'd feel differently if this were our "startup idea" and our success depended on that traction/audience.
However, we're always interested in people who do machine learning for a living [not just blogging/YouTubing/Mediuming/Tweeting/Audiencing about it] using our platform[0]. They may be dealing with problems we haven't seen, working on interesting projects, and it's always a blast to talk with these people.
For example: you get a huge boost in rankings when you first launch an app in the App Store. Not enough to be #1 above a Calm, but certainly #1 for medium-difficulty keywords. Once this advantage goes away, you'll need a strong ASO strategy and money to spend on ads to boost keywords.
Some of these opportunities are tough to overcome after you missed them. Press is very similar: reporters will cover a newly launched product, but new features likely won't get a feature.