I'm in the process of starting a new web site that is something like stackoverflow but a little bit more different along with making the members profiles highly more customizable I was thinking of building it from scratch using PHP, but was thinking of using CakePHP, but then I thought WordPress sounded better but I remember working with wordpress and it was a little bit slow at times when you tried to browse the web site.
So what I guess I'm trying to ask is that should I design the site from scratch? And I heard techcrunch.com and 9rules.com are completely done in WordPress, is this true?