My partner just created her #Threads account and the account that showed up on top as suggestion to follow was mine. However, I don't have a Threads account.
Basically, anyone who has an Instagram account, #Meta is automatically creating a shadow account for them and also allowing users to follow those shadow accounts. My partner had tonnes of follow requests as soon as she made the account.
Instagram has over a billion users.
Their user count is the number of Instagram users that have activated threads.
If you follow someone who hasn’t, it will automatically follow them if they do activate. That doesn’t mean they created some shadow profile.