How did Shopee – a small e-commerce player launched in 2015 – overtake its historic rival Lazada in just a few years to average 281 million visits a month and become the most valuable company in South East Asia in 2021? CEO Forrest Li followed a bold two-sided digital marketing strategy that won over sellers (B2B) and users (B2C).

Social commerce is a new trend in e-commerce that leverages individual relationships and affiliations to drive growth in online sales. The case compares two companies, Pinduoduo and Facebook/Instagram, and their different social commerce business models, notably social network based vs. social group based models.