This is article is pretty much the same experience I had. Albeit we launched June 12th (pretty much, the last day of Startup School).
We built a super rough MVP during throughout the duration of Startup School. Here's our product if anyone's interested:
It's basically a search engine meets your news feed. We're specifically targeting financial advising, while keeping an eye on enterprise search.
Launching it so late, had it's draw backs, but also IMO was the right for us. We got to see everyone else's progress, but we also did follow much of the advise: interviewing customers, launching pre-registration, how to structure a company / team, etc. We also got to see other teams mistakes, and successes.
I think that's what I found super valuable, not so much where people were from, but the various stages of their startups! We had people come in with only ideas, and watched them bring them to launch. Some people grew their company 10x. It was fun and interesting to watch the process.
We also had several people interview for the Summer YC class, while in startup school. I've previously interviewed, so I knew what it was like - but others (and I to some extent) found it valuable to ask questions and understand what they look for. Some companies in our group, I'm sure, will be looking for funding.
NPS and sentiment analysis is pretty good for elections and predicting social events. Sentiment analysis (or what we call Expert Opinion) is slightly better for predicting stock and crypto movement(s).
We invested last year using our stock advisor:
And this year into crypto currencies:
The real trick, is how we improve signal to noise ratio.
I don't know the cost, but my system needs quite a bit of on boarding at the moment. So, kudos for definitely hitting a product-market fit.
We have people signing up with the credit cards, and we're still building out the MVP so... We're relatively content at the moment. Plus, we're really only looking for people who have incentive to say:
"Hey, your product sucks you need to fix X, Y and Z or I'm out!"
Best of luck!