Besides gaining reputation with your questions and answers, you receive badges for being especially helpful. Badges appear on your profile page, flair, and your posts.

Question Badges

Asked a well-received question on 100 separate days, and maintained a positive question record
Question favorited by 100 users
Question score of 100 or more
Asked a question with 10,000 views
146 awarded

Answer Badges

Edited and answered 500 questions (both actions within 12 hours, answer score > 0)
Answer score of 100 or more
Highest scoring answer that outscored an accepted answer with score of more than 10 by more than 2x
Provided answer of +20 score to a question of -5 score
Zero score accepted answers: more than 10 and 25% of total

Participation Badges

Visited the site each day for 100 consecutive days. (Days are counted in UTC.)
13 awarded
Earned 200 daily reputation 150 times

Tag Badges

You must have a total score of 1000 in at least 200 non-community wiki answers to achieve this badge.

Moderation Badges

Raised 500 helpful flags
Served as a pro-tem moderator for at least 1 year or through site graduation
5 awarded
Served as an elected moderator for at least 1 year
Completed at least 1,000 review tasks. This badge is awarded once per review type
Edited 500 posts (excluding own or deleted posts and tag edits)
Voted on 600 questions and 25% or more of total votes are on questions
4 awarded

Other Badges

Shared a link to a question that was visited by 1000 unique IP addresses