In a previous post, [1] I finished with a quote from a New Yorker article by Craig Mod, in which he suggested some different types of data that might be gathered and ‘pinned’ to the ‘back’ of a digital photograph.  Amongst the data he suggested we might collect were “location, weather, even radiation levels […] social status and state of mind”, in other words data drawn from sensors and from social networking sites such as Facebook and Twitter. [2]  I made the point then that there is a huge difference between data taken from a sensor and data from taken from Facebook, the first is reliant on measuring some kind of physical quality; the second, the expressions of people.  I stand by that point, but now I want to examine the two in a little more detail. Continue reading →