I've got some time to make a major push in developing some new content on a subtopic of a general topic (like sportcars is a subtopic of automobiles). I already have one website directly on target with this field (say it's name is automobiles (dot) com). The website is fairly decent, you would probably consider it to be in the lower end of the top tier of websites in its field. My question is this. Would it make more sense to add this new content to my existing site (automobiles (dot) com) as a subtopic, or would it make more sense to start a new domain (with an exactly on-target two or three word domain name like hotsportcars (dot) com)? How important is the boost in traffic you might get from a directly on-target domain name? Is the boost you might get worth going through the hassels of developing a new domain (I guess I'm referring to the sandbox effect)?
