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 30 separate days, and maintained a positive question record
3 awarded
Question favorited by 25 users
31 awarded
Question score of 25 or more
74 awarded
Asked a question with 2,500 views
54 awarded

Answer Badges

First to answer and accepted with score of 10 or more
9 awarded
Edited and answered 50 questions (both actions within 12 hours, answer score > 0)
Provided non-wiki answers of 15 total score in 20 of top 40 tags
Accepted answer and score of 40 or more
Answer score of 25 or more
5 awarded
Answered a question more than 60 days later with score of 5 or more
44 awarded
Zero score accepted answers: more than 5 and 20% of total
1 awarded

Participation Badges

Voted for a candidate in the final phase of an election
Left 10 comments with score of 5 or more
1 awarded
Visited the site each day for 30 consecutive days. (Days are counted in UTC.)
131 awarded
Earned 200 daily reputation 50 times
10 posts with score of 2 on meta
Posted 10 messages in chat that were starred by 10 different users
Active member for a year, earning at least 200 reputation
529 awarded

Tag Badges

You must have a total score of 400 in at least 80 non-community wiki answers to achieve this badge.

Moderation Badges

Raised 80 helpful flags
1 awarded
Voted 300 or more times
7 awarded
Completed at least 250 review tasks. This badge is awarded once per review type
Edited 80 posts
3 awarded
Edited 100 posts that were inactive for 6 months
Up voted 100 answers on questions where an answer of yours has a positive score
Edited 50 tag wikis
Created a tag used by 50 questions
4 awarded

Other Badges

Shared a link to a question that was visited by 300 unique IP addresses
1 awarded
Participated in the private API beta; +2000 rep bonus
44 awarded