Peer voting on questions and answers gives users most of their reputation, and also usually controls how posts are sorted to the top.
The default sorting option on answers is by vote, with accepted answers by others pinned to the top. Questions in search results, user profiles, and tag pages are also often sorted by vote.
Badges related to the whole act of voting on posts by other users include:
- Supporter — First up vote
- Critic — First down vote
- Civic Duty — Cast at least 300 votes
- Electorate — Of all your votes ever cast, at least 25% and at least 600 total have been on questions
- Suffrage — Used 30 votes in a single day
- Vox Populi — Spent the maximum of 40 votes in a single day
- Sportsmanship — You've upvoted 100 competing answers on questions you have provided an upvoted answer to