Influencers are often ordinary people that gain fame and earn a living through sharing their life and opinions, whilst key opinion leaders (KOL) are top professionals in their field who already have an established reputation. The credibility of key opinion leaders (KOLs) is higher than influencers. The positions and identities of key opinion leaders (KOLs) are usually more clear and exclusive than influencers. With the rapid development and usage of social media, both KOLs and influencers reach their audience through various social media platforms. KOLs are most often influencers, but not all social media influencers are KOLs.