I’m a customer of Whatsapp Inc, an instant messaging service. It is subscription based service in which the first year for free and any additional year is charged at 0.99 cents. Their promotional activities is mainly through their own blogs and social media (Twitter, Facebook, and LinkedIn). Also paid advertising. They do have various tech blogs and news writing about them. In my opinion, their PR and community management activities are geared towards people at the top of the funnel, where they are creating awareness and getting people’s interest in the app by keeping it free for the first year of usage. I haven’t seen and referral promotions so far. They can improve their activities by having weekly newsletters, more advertising on Youtube, promotional updates to customers and having an option/blog on their site for customers to comment or link their blogs.