> means “is a child element of“. So body > *:not(.toolbar) matches *:not(.toolbar) that is a child of body.
*:not(.toolbar) matches any element that does not have the class .toolbar.
*[selected="true"] matches any element with the selected attribute equal to true.
Keep in mind that the last two (*:not() and *[] are part of the CSS3 spec and you usually can’t rely on them for cross-browser CSS compatibility. They are, however, fully supported in WebKit.