I worked on a web site ranking on the first page in Google. The "2 words" keyword is not include in the url and the PR for the site is only 5, most links being internal. The competion for that keyword? 2,880 for the exact term and 377,000 for a regular search. Have I optimized the page for that specific keyword? Yes but it wasn't my main focus since I had other keywords being more important on that page. (Yes I ranked fairly well for those too ;-)) It seems to me that Google is not paying that much attention to link popularity.