I read somewhere that if you will optimize your pages for some high traffic keyword spelling mistakes, you can get some high quality traffic from this. I really dont know how much this will help you as I have seen google corrects the spell mistake done by searcher and then there is very less chances to get traffic from this method. In past I did noticed some traffic is coming from this method( but I have not optimized my pages for this reason nor used any such keywords in my content) like for my site theory-test.co.uk I used to get traffic for the keyword "thoery test" instead of my targeted "theory test". I assume google not entertain spell mistakes in URL as well, for e.g. Dmooz.org instead of dmoz.org etc. Question is, Is this method helps, if yes why google not supports this URL thing?