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

Answer Badges

Edited and answered 1 question (both actions within 12 hours, answer score > 0)
14 awarded
Answer score of 10 or more
60 awarded
Answered more than 30 days later as first answer scoring 2 or more
18 awarded
Answered your own question with score of 3 or more
9 awarded
Answered first question with score of 1 or more
292 awarded

Participation Badges

Completed "About Me" section of user profile
880 awarded
Visited an election during any phase of an active election and had enough reputation to cast a vote
Left 10 comments
66 awarded
Earned at least 200 reputation (the daily maximum) in a single day
1 awarded
Followed the Area 51 proposal for this site before it entered the commitment phase
37 awarded
One post with score of 2 on meta
36 awarded
Posted 10 messages, with 1 or more starred, in chat

Tag Badges

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

Moderation Badges

First flagged post
50 awarded
First rollback
4 awarded
First down vote
83 awarded
Completed at least one review task. This badge is awarded once per review type
82 awarded
Deleted own post with score of 3 or higher
1 awarded
First edit
194 awarded
Edited first post that was inactive for 6 months
10 awarded
First retag
26 awarded
Deleted own post with score of -3 or lower
3 awarded
Approved or rejected 100 suggested edits
1 awarded
Used 30 votes in a day
9 awarded
First up vote
493 awarded
First approved tag synonym
4 awarded
First tag wiki edit
17 awarded
Used the maximum 40 votes in a day
8 awarded

Other Badges

Visited every section of the FAQ (retired)
27 awarded
Shared a link to a question that was visited by 25 unique IP addresses
Read the entire tour page
78 awarded