Rep (reputation) power is indicated by a number and green (good) or red (bad!) bars. If you meet the basic requirements in length of membership and post count you can add to someone's reputation score by clicking the scales icon at the bottom of the frame below their avatar. If your reputation power is 2 you will add 2 points to their reputation.

You can change your reputation by doing good deeds or bad deeds. A good deed might include donating money to someone who needs it, or being helpful on the boards in a way that gets attention from others and they add to your reputation. A bad deed might be junk posting, advertising, or using the Thief feature in the store!

Your reputation points (visible in your User CP) are proportional to your reputation power. Your reputation points must change by 500 or more before your reputation power changes. Reputation power diminishes over time. You can do good deeds this week and gain rep power, but if you revert to your evil ways you'll notice your power diminishing with time.

You can see who has affected your reputation in your User CP.

Regular members can add to your reputation score so long as they meet the minimum requirements. Board staff can both add and subtract from your reputation score - if a staff member feels your infraction is serious enough, you may notice not only a drop in your reputation score, but a CPF cash penalty as well!

As far as we can tell, your reputation score plays a role in how easy it is to thief from you! Of course, wise CPF members know how to protect themselves from dirty scoundrels anyway! (Read more here)