Hi John,
From What I have observed:
You're Popular - You get this badge when you have around 100 followers
Influencer - You get this badge when you have around 250 followers
Super Influencer - You get this badge when you have around 500 followers
Thought Leader - You get this badge when you your blogs get lots of replies, lot of bookmarks and likes and lot of 5 star ratings
5th hidden badge is Pay It Forward - for earning this badge you need to comment, rate, like, bookmark and share blogs or documents
Regards,
Vivek