its not a new way... thats how most websites make their money... analytics basically its a type of information that tells you what your clients like, do and want... if you know those things... you can make money... its like a insight of the market... for example : thats why google is worth billions... we all use googles engine... google knows everything we do... not necessarily knowing our names.. but knows that some areas in some countries likes eating pudding... so they place ads of pudding in that IP address area... in other parts they like to eat beef jerky and they advertise it there... and so on and so forth ... they now sell ads spaces on their market etc... thats how internet worked from very beginning, its nothing new...
if you ever asked yourself how some websites that dont have ads and dont sell their own products make money(like the websites where you sell your stuff... but they dont charge you anything?)(ie. olx[dot]ro)... then the answer is simple... they track what you buy and sell and what is it that you like hate etc... and sells that information to advertising companies... that builds and updates their market information... and then sell their ads to other businesses that wants to advertise their products or activity... now they are plenty of sides of analytics and the advertising business but this is what stays at the core of it... the most simple structure existing...
we also use analytics in games... for example... on a app - you have users that like the gameplay but hate the blood and gore..on other app - they like that you have items on sale and that they are not expensive... now on your next app you know what to avoid and what to do so it gets a more balanced and fine tuned selling product.
analytics is basically another way of forcing people to tell you what they do...like a poll vote or a questionnaire but without an actual consent.(the consent comes from the terms of agreements when they choose to accept it using your app).
there is plenty of information out on analytics and cookies and tracking scripts ... but thats another story
now how you convert the info into cash... dont know... i have no clue where you can sell it... but im guessing the website you said its one of those buyers... which pays you not even close to the real price... but hey its an extra coin you can bring from your apps...