"I didn't have an automatic right to use Google's service in an innovative way. And indeed, I tried it anyhow, just to see how they reacted, the server stopped

"I didn't have an automatic right to use Google's service in an innovative way. And indeed, I tried it anyhow, just to see how they reacted, the server stopped responding after the first 50 or so hits." No, you didn't have the automatic right to use their servers as much as you want in an innovative way. Putting in a time delay (say 2 seconds?) between each request and you can do that just fine. Google is in no way saying either method is inappropriate, just that they consider one to be an action done by businesses and they don't give away as many services to businesses for free. I hope you got the list done for your friend though, it sounds like quite a nice thing to do.