What are "fans," "unfollowed," "cross-followed," and "inactive?
SocialDog categorizes followers and followers according to their status as follows
Unfollowed: users who are following you but not following you (you can unfollow them)
Fans: users who are followed but not followed (can follow back)
Cross-following: users who are following and being followed
Inactive: users you follow but have not tweeted recently (including retweets)