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

Ask a good question on 100 separate days, and maintain a positive question record
Question favorited by 100 users
2 awarded
Question score of 100 or more
7 awarded
Question with 10,000 views
164 awarded

Answer Badges

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

Participation Badges

Visit the site each day for 100 consecutive days. (Days are counted in UTC.)
66 awarded
Earn 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

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

Other Badges

Share a link to a question later visited by 1000 unique IP addresses
13 awarded