This badge is based on the number of people who follow you while under the community you would like this badge for, so the person following you must be under the community in question for it to count for that community.
For example: If 100 people follow you while under Justin Bieber, but your total number of followers is 500, and you want the 500 badge, you will only get the buddy badge 100 (For Justin Bieber community) and not 500. Since the additional 400 where viewing a different community when they followed you.
The number you see in your profile (ex:500) is Global. So once the set number of people follow under a specific community you will get the next badge.
So just make sure you tell the community to follow you while in that community.
The number of exact followers is not visible in user profiles at this time. However our system checks every day for the count to apply the correct badge.
*Required for status changes/updates.
Awarded: Automatically