This is necessary for personal search engine and personal knowledge graph. The essence of personal data ownership and Situated Software is having access to and agency over all the data that you consume and produce. The problem right now is that we produce and consume data on a bunch of differnt devices in different contexts, like our computer, our phones, and even physical books and artifacts. In order to create a digital repository of all of the information that we consume and all the thought that that input triggers, we need to be able to access the data that we view through all these varied mediums. In many of these, we need to plug in at the operating system level in order to track everything. This can be harder in more closed ecosystems like the iOS one. Ideally, all this data would be available to us in a uniform format (perhaps several data formats to support different use cases of querying data). Varied data formats enable playing with your data