[NTG-context] Understanding ConTeXt better. What does \doattributes do?

Hi, I've been reading the Document Titles page on the wiki http://wiki.contextgarden.net/Document_Titles. I'm trying to better understand how ConTeXt works. Could someone explain what \doattributes does? It doesn't appear to be covered in the Inside ConTeXt section of the wiki. Also on the subject of Document Titles. Why is it that \setuptitle is called several times at the end of the source code? TIA, Elliot