Members can express their opinions of a post by voting. The choices are Vote Up, Vote Down or "Bull's Eye."
When you Vote Up (represented by a 'thumbs up' symbol), your vote is recorded by displaying or increasing the number next to the vote. Also, the author is given some points to his YourView 'rank' which is a measure of his reliability and trustability.
When you Vote Down (a 'thumbs down' symbol) the post becomes visibly a little more transparent, indicating that it is less important than others.
When a post really does a great job answering a question, give it a 'Bull's Eye.' The post gets a little more opaque and pronounced to indicate that it is considered to be more important, and the author earns more points.
How can I trust an answer to my question? One way is to look for the author's Rank.