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 well-received question on 100 separate days, and maintain a positive question record
2 awarded
Question favorited by 100 users
Question score of 100 or more
1 awarded
Question with 10,000 views
105 awarded

Answer Badges

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

Participation Badges

Visit the site each day for 100 consecutive days. (Days are counted in UTC.)
43 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.

Moderation Badges

Raise 500 helpful flags
1 awarded
Served as a pro-tem moderator for at least 1 year or through site graduation
4 awarded
Served as an elected moderator for at least 1 year
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)
2 awarded
Vote on 600 questions and 25% or more of total votes are on questions
17 awarded

Other Badges

Share a link to a question later visited by 1000 unique IP addresses
http://biology.stackexchange.com/help/badges?tab=General&filter=gold
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