Over the past decade, our cities have been blanketed with digital bits. Unlike the old electromagnetic, unidirectional waves, these bits are bidirectional - they communicate - and are thus tied to human activities. Our hypothesis is that by analyzing these bits we can gain an augmented, fine-grained understanding of how the city functions - socially, economically and yes, even psychologically. Some preliminary results from different projects recently carried out at MIT senseable city lab are discussed below.