Ethan Garner has been collecting data on rents in San Francisco based on craigslist postings since Aug 2006. Based on this data, he has created a lovely visualization of where the rental market is hot (via information aesthetics).
Garner claims to have created this project out of boredom, while a grad student in biochemistry at UCSF. I don’t believe it. He’s clearly got a passion for coding, and with the vast amount data out here on the internet easily mined or already collected, this guy will never be bored.