There are several ways to look at different types of social media influencers. The most common way is to segment social media accounts by their reach, measured in number of followers. Although not necessarily an accurate indicator of someone’s actual influence on a topic, it is a good initial indicator to sift through large numbers of users. Using this method marketers roughly separate four groups, as described in this (summarised) post by the Influencer Marketing Hub (source):
Mega influencers are people with a vast number of followers on their social networks. Although there are no fixed rules, a common view is that mega-influencers have more than 1 million followers on at least one social platform. These people are often celebrities who have gained their fame offline, like movie or television stars, sports people, musicians and key politicians.
Macro-influencers are one step down from the mega-influencers. You would consider people with followers in the range between 40,000 and 1 million followers on a social network to be macro-influencers. This group tends to consists of two types of people. They are either B-grade celebrities, who haven’t yet made it to the big time. Or they are successful online experts, who have built up more significant followings than the typical micro-influencers. The latter type of macro-influencer is likely to be more useful for firms engaging in influencer marketing.
Micro-influencers are often people who have become known for their knowledge about some specialist niche. As such, they have usually gained a sizable social media following amongst devotees of that niche. Of course, it is not just the number of followers that indicates a level of influence; it is the relationship and interaction that a micro-influencer has with his or her followers. Although views differ, you could consider micro-influencers as having between 1,000 and 40,000 followers on a single social platform.
The newest influencer-type to gain recognition is the nano-influencer. These people only have a relatively small number of followers, but they tend to be experts in an obscure or highly specialized field. You can think of nano-influencers as being the proverbial big fish in a small pond. In many cases, they have fewer than 1,000 followers – but they will be keen and interested followers, willing to engage with the nano-influencer, and listen to his/her opinions.