Karma: Karma is a measure of your interactions and contributions to hello. You are awarded karma points when people interact with your content. The more unique and interesting your jots, the more karma points you can receive. The more karma you receive over time, the more you level up and unlock new features.
Achievements: Achievements show your progress over time. Complete various requirements to unlock achievements.
Milestones: Milestones are reached by performing positive actions (such as hearting, commenting and posting) a certain number of times. There are multiple milestones per action, each harder than the previous. Reaching a milestone will award you karma.
Note: Spammy behavior is frowned upon and can negatively impact your karma, user level, and ultimately persona reputation.