That's due to a combination of crime, local businesses (e.g. fancy coffee shops and bars), and access to commuter shuttles. You can see some of these in heat ma

That's due to a combination of crime, local businesses (e.g. fancy coffee shops and bars), and access to commuter shuttles. You can see some of these in heat map form here: http://www.trulia.com/local/san-francisco-ca/ http://www.trulia.com/local/san-francisco-ca/