The number of an influencer’s followers on social networks is calculated as such:
Facebook followers
Facebook followers metrics can come from two different sources: a Facebook page or a Facebook profile, depending on which one the influencer is using. For a Facebook page, followers are defined as the number of page likes. For a Facebook profile, followers are defined as their number of friends.
Twitter followers
Twitter followers are defined as the total number of people following this profile on Twitter.
Instagram followers
Instagram followers are defined as the total number of people following this profile on Instagram.
YouTube followers
YouTube followers are defined as the number of subscribers to the channel.