With as many as 150 million users everyday, Snapchat is undoubtedly gaining popularity even more than Facebook & Whatsapp.
There are many reasons triggering the growth of Snapchat in India as well as across various countries. One of the major reasons is an increasing tendency by users to incline towards more visual mediums. due to the ever-decreasing attention span of the target audiences, it has become crucial to keep the social engagement short, crisp and precise to address the need of the users. Snapchat is one such application that allows marketing initiatives to bring together a collection of photos and videos which are weaved together to create a complete story.
As far as examples are concerned, know how McDonald's & Audi have used Snapchat for different business objectives: http://www.digitalvidya.com/blog/brands-use-snapchat-for-social-marketing/ .
Hope this helps?