what is the business model here? Sorry, I am confused here and website is not explaining it correctly. I dont see what kind of "premium numbers" are available.

what is the business model here? Sorry, I am confused here and website is not explaining it correctly. I dont see what kind of "premium numbers" are available. Why would someone pay to talk to me? would the caller have to register and provide CC number? Is this call-back model which was used few years back on some website where some voice companies would offer call-back option from website (I think it used java that time) and it would cost per minute.