I don't think you need to change the domain name. For marketability, you might wanna have the parts named so that stuff within your site becomes brand in itself, so greatplay.net becomes associated with "<brand name> utilitarianism", "<brand name> design" etc. Say, I read a blog by a chemist who has series of blog posts titled "stuff i won't work with: <stuff name>". I can't remember the domain name, but I know that whenever I want to read about nasty chemical, i google that phrase.