Pinterest basically displays all the product in an intuitive way from merchants. Say, jabong has tons of cute dresses, but when someone goes to jabong, they can't find "cute dresses". Instead, Pinterest decides to add a cute tag to some really cute dresses.
Therefore, a gal who wishes to find some cute dresses can end up going to pinterest and there she can get all such dresses tagged by the members.
The advantage to pinterest here is that if the gal decides to buy through pinterest, Pinterest will earn a commission.
In non-tech terms, when you check out a product on pinterest, there's a button called "Visit site". This button includes an affiliate link. An affiliate is someone who promotes/endorses products for a 3rd party (called a merchant or a vendor or an advertiser).
The merchant pays for every sale to Pinterest if the visitor is sent through their site. As simple as that.
There are a lot of indian affiliate networks like OMG India etc which help drive sales for all merchant sites through such mediums.
Hope this was enough to answer your queries!
Last but not the least, even thinkdigit forum is an affiliate of DGM India, as they have placed a Yatra.com banner at the end of their homepage. Every time some TDF member clicks on their banner, buys a ticket on yatra, TDF will be paid a commission for that.
