they made it so they could get money

and we pay them through our internet service like Comcast or whatever

Take a look at the right side of the page in your question.
You will see “Sponsors” to Yahoo! Q&A.
A sponsor is a person or entity that pays you to do what you do.
These sponsors are rewarded with a little innocuous add/link in questions.
You may notice how those questions change in response to what questions are asked.
This key target marketing gets the most responsive eyes looking at them.

They earn in million by show ads of other products.Now a days earning online is an easy way when comparing to others.