I think in essence they made a load of deals with various suppliers, initially insurance companies, saying something like: you give us access to your quotation services, we’ll drive business to you, you pay us a commission for any business you receive. And somehow managed to get them to agree.
Which platform/language/any CMS(or script)/backend is used by top price comparison website?
I don’t think you can say. I had look at gocompare’s website and they have a posting for a web development manager job there but it doesn’t even mention any technologies in the job description. If I had to guess I’d say they have to interface with all sorts of different things. There’ll probably be one language and platform they use to bring it all together but it could be anything. People can do amazing work with really bad tools sometimes.
Perhaps the question you mean to ask is: if I were to build a price comparison site what technology should I use? But my answer would still be it doesn’t really matter because by far the most challenging part of starting a price comparison site is getting the opt-in from the suppliers. And what are you going to do differently from all the others? The market is pretty crowded now.
How exactly do they track particular users if there is no provision of confirming user from affiliate provider(merchant) end?
If you look at the URL from an affiliate to a product on Amazon you’ll see there’s an affiliate id in there. So if the user follows that link and then buys the product Amazon knows to give some percentage to that affiliate.
How meta search engine work and how can it be built up?
I actually don’t know. There’s the hacky way, which is where every search performed with the metasearch engine triggers a series of automated searches on various different search engines which are then aggregated. But I think that would be in violation of the terms of service of the search engines. So while that is technically sound way of achieving it there has to be some deal making going on as well otherwise the search engines would just block the metasearches and that would be the end of it. One example, I believe Yahoo’s search results were powered by Google for a while:
So clearly there is plenty of deal making going on between these companies. Exactly what the terms of the deals are can only be speculated upon.