Visual presentation and appeal, whether in your marketing materials or what you wear, can turn on or turn off what people you attract. It does not matter if it's on paper matter, the Internet, like a web site, or in a presentation.
Colors tell someone if you are approachable. In the same way they will affect whether someone will continue clicking through your web site.
Colors will determine if someone will start reading your article in a magazine or posted on your web site. Color also helps to keep people involved on your web site (it's not just about the content) and how long they stay.
Colors also influences how people will respond and behave. A black background on your web site now represents sex-type of web sites. It is important that if that isn't your focus that you don't use a black background.
In America, green is associated with jealousy or money. Here are some color references for America.
