Knowledge bases, or FAQ's as they are often called, is a great way to reduce repetitive questions from clients over email or phone.
Every time you get asked a standard question, add it and the answer to your knowledge base, then direct the next person to ask the question to it.
Our knowledgebase addon is entirely managed by you: You can add as many questions and answers as you want, and even add additional staff as "editors" to help manage things.