Each vote generates a revenue for the post depending on how much Steem Power the voter has. But Steem Power is not the only factor here. Your voting power determines how much of your Steem Power can be used. You can have an account that has millions of Steem in it but if your voting power is reduced to 0, then your votes won't produce any revenue for the post which is the main factor in causing the post to go viral on the site. I don't have any links to the mathematical calculations behind it, to be honest.