Statistics I'd say is one of the useful cases of scraping.

Back in 2013, a guy scraped the results of about 150,000 students giving their 10th grade finals of a particular examination board in India. He showed that not only was there no privacy of student's marks because the roll numbers were all linearly incremented, but there was also mass-scale manipulation of marks going on.

The concept is simple but it's a very interesting read.

https://deedy.quora.com/Hacking-into-the-Indian-Education-Sy...

I was one of the 150,000 kids that gave those exams back in 2013 :)