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
2 awarded
Question score of 100 or more
1 awarded
Asked a question with 10,000 views
362 awarded

Answer Badges

Answer score of 100 or more
3 awarded
Highest scoring answer that outscored an accepted answer with score of more than 10 by more than 2x
1 awarded
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.)
43 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.
2 awarded

Moderation Badges

Raised 500 helpful flags
Served as a pro-tem moderator for at least 1 year or through site graduation
7 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
3 awarded
Voted on 600 questions and 25% or more of total votes are on questions
12 awarded

Other Badges

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