What is Reputation?
Reputation is an optional way to represent the community's trust in you. Earning reputation is easy! You get points every time someone votes up one of your posts or successfully follows a repair guide you contributed to. For example, you earn 30 points if someone says that your answer solved their problem.
You can always ask a question or post an answer. As your reputation increases, the system trusts you more and gives you access to more powerful features.
Your reputation can go up and down based on how others perceive you, just like it would in real life. Certain actions, such as voting down a post, cost a little bit of reputation. Not much, but enough to encourage you to be sparing with your criticism.