There are two levels of entries: Comment only and authenticate + subscribe.
Comment-only entries (no bonus entries)
When your followers comment, we use the Instagram API to check the comments on your post. If the follower makes a comment that qualifies (e.g. completed the number of tags you set), they are entered to win.
Comments are checked to prevent fraudulent entries, prevent duplicate tags, etc.
Authenticate + Subscribe entries (bonus entries)
To get bonus entries, followers must also authenticate and subscribe to your newsletter or list via email on the campaign entry page.
To authenticate user Instagram accounts we use the official Instagram user authentication API service managed by Instagram.
To confirm email subscription, we use double opt-in validation. This means we send an email to the email address the user entered that they must confirm. Once they confirm, they get the bonus entries and are added to your email list.