Social media helps to develop aspects of commerce that are facilitated by expanding personal networks, such as peer-to-peer selling. The impact on other forms of commerce is more variable.
Here we see one of the main reasons why social media is especially important for commerce that involves personal relationships - the role of trust.
As part of the everyday exchanges of jokes, porn, religious messages and general gossip, people also use WhatsApp to sell goods to their friends.
Facebook has become a huge site for buying and selling in a town with surprisingly few formal commercial outlets for its size.
Most commercial companies try to have a presence on social media, but it is the businesses that rely on personal connections which find it most worthwhile.
In this film, a professional expert on social media shows how he promotes a daily daily cycle of postings for companies.
In China, even the largest commercial platforms try to add a personal touch. Taobao (similar to Amazon marketplace) has a built-in social media feature, so that most buyers and sellers message each other before a sale.
Social media did not seem to have much of an impact on commerce here, except as free advertising for local small businesses and events.