Why is structured querying of your personal data important? Self-reflection.
Example in point: seeing what I’ve quoted, from who, about what, and what I’ve said about the quotes. How it’s changed over time. How I talk about it and present it in my personal context. From a technical point of view; how I mark it up.
Twitter does the opposite of this, and encourages us to throw away our history, much less peruse it and learn from it. Facebook aims to present a glorified timeline emphasising the most “important” events in our life. I feel neither are particularly valuable.