Nearly every industry in India has adopted social media marketing. According to a Goldman Sachs report, the Indian digital marketing business is expected to be worth $160 billion by 2025. Digital marketing is expanding quickly in India as consumers have been inspired to purchase from a new brand after seeing social media images or posts, thus it has been found that 71% of consumers are more likely to make a purchase based on social media referrals. Therefore it is important for us to understand how social media has influenced consumers' purchase behavior. Therefore the research aimed to investigate the factors that influence customer buying decisions through online forms of marketing (social media) by comparing it with offline forms of marketing(billboards), by making use of the advertisements provided by the multinational company Starbucks. The research also aimed to investigate why individuals are more convinced to buy a drink through social media than through offline marketing. The research was conducted on 40 customers of Starbucks in India, and Mumbai, most of them being students who follow Starbucks on various social media platforms. Data was collected through an online questionnaire sent through google forms. The results of the research indicated that since social media marketing makes use of various creative elements(music, graphic,s and colors), customer testimonials and helps satisfy a need, which gives them social proof, individuals are more convinced to purchase a drink from Starbucks than through offline forms of marketing. This concludes that social media marketing is more effective than offline marketing since it gives social proof, and therefore has a more significant effect on consumers' purchase behavior.