I have also thought about this issue while developing content for my own website. The last thing I want to do is make myself look dishonest or a fraud. My opinion is that you do not have to cite everything that you find by a third party. All information that you get or find will always come from a third party unless you were there, or made the news yourself. Some things are just common knowledge. For example we all know that the Declaration of Independence was signed on July 4 1776. This is common knowledge and I do not believe you would have to cite this just because you read it out of book xyz. If you take general ideas and put them into your own words, thoughts or develop your own ideas then it becomes your original content. On the other hand I do believe you must cite or give credit to information that is derived from someone else's original idea or thesis or if you use their information word for word. Sometimes you may also have to dig for information and can only find it from one or two sources. I would also reference this source because the information is not so common. Hope I got my ideas through without rambling on. Thanks.