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

First bounty you manually awarded on another person's question
3 awarded
First bounty you manually awarded on your own question
5 awarded
Asked a well-received question on 5 separate days, and maintained a positive question record
53 awarded
First bounty you offered on another person's question
4 awarded
Question score of 10 or more
113 awarded
Asked a question with 1,000 views
70 awarded
First bounty you offered on your own question
7 awarded
Asked a question and accepted an answer
341 awarded
Asked first question with score of 1 or more
498 awarded
Asked a question with no votes, no answers, no comments, and low views for a week

Answer Badges

Answer score of 10 or more
160 awarded
Answered more than 30 days later as first answer scoring 2 or more
25 awarded
Answered your own question with score of 3 or more
13 awarded
Answered first question with score of 1 or more
919 awarded

Participation Badges

Completed all user profile fields
624 awarded
Visited an election during any phase of an active election and had enough reputation to cast a vote
Left 10 comments
150 awarded
Earned at least 200 reputation (the daily maximum) in a single day
6 awarded
Followed the Area 51 proposal for this site before it entered the commitment phase
43 awarded
One post with score of 2 on meta
59 awarded
Posted 10 messages, with 1 or more starred, in chat
5 awarded

Tag Badges

You must have a total score of 100 in at least 20 non-community wiki answers to achieve this badge.
2 awarded

Moderation Badges

First flagged post
111 awarded
First rollback
14 awarded
First down vote
138 awarded
Completed at least one review task. This badge is awarded once per review type
193 awarded
Deleted own post with score of 3 or higher
3 awarded
First edit
497 awarded
Edited first post that was inactive for 6 months
36 awarded
First retag
40 awarded
Deleted own post with score of -3 or lower
5 awarded
Approved or rejected 100 suggested edits
2 awarded
Used 30 votes in a day
21 awarded
First up vote
823 awarded
First approved tag synonym
First tag wiki edit
17 awarded
Used the maximum 40 votes in a day
7 awarded

Other Badges

Visited every section of the FAQ (retired)
37 awarded
Shared a link to a question that was visited by 25 unique IP addresses
7 awarded
Read the entire about page
135 awarded