When they were big in the U.S. (976-xxxx days, before they moved to 900-xxx-xxxx), they were mostly astrologers, fortune tellers, and phone sex lines.

The only one I've seen in a very long time was for a psychic reading over the phone.

"I predict... you will lose a modest amount of money...."

Once upon a time redirects were used as pricing mechanism for phone-based "apis". So you could call some weather forecast, or sports analysis, yada yada. I don't know if these still exist, it would not surprise me if redirects are used mainly for fraud nowadays (they are huge in voip call centres breaches).

Believe Shazam also started as such a dial in service.

Indeed - I bought some early Bluetooth headphones that have a 'shazam' button, and pressing it would Dail their 4 it 5 digit UK number at the time. I think it was something like 2580 (the numbers straight down the centre of the dial pad.) Calls were capped at 50p I think and you got an sms response with the song title and artist fairly swiftly.

Strange how fast things change hey! Old news article about shazam and aqa https://www.cnet.com/uk/news/shazam-aqa-the-answer-is-on-you...

This company described the service as 'revenue sharing' .. http://www.callagenix.com/numbers/090x-premium-rate-numbers

If you own a business, you give your redirect, expensive number to clients you don't care much about so they don't call bitching about stuff (quality of whatever you sell, etc) and then you give your direct, free number to clients you don't want to lose.