Hi,
Quora is very useful for everyone. I am using it from last 3 months and I found almost everything on it. Professional knowledge or personal information. You can also write your views on it. You just have to look for the topic on which you want an answer. The views you gets are from very professional players. You can check the details of any product or for freelancing projects. Quora provides you to answer the questions which people asks. If you are an expert in some profession, you can give your views on the questions.