What does it say about these two cities that San Francisco has only 1/4th as many people as Chicago*, but on Craigslist** there are 4 times as many resumes posted?

*I did a Google search for populations, and it told me that Chicago's population is 2.8 Million, and SF's population is 744,230.
**On Craigslist's main SFBay page: 7484 resumes. On Craigslist's main Chicago page: 1715 resumes.