Facebook suggests not only a moral imperative to place certain information in its network, but the broad applicability of one template to compare people. In this it is distinct from Google, which encourages semistructured online activity that Google will be best at organizing after the fact.
Twitter suggests that meaning will emerge from fleeting flashes of thought contextualized by who sent the thought rather than the content of the thought. In this it is distinct from the Wikipedia, which suggests that flashes of thought be inserted meaningfully into a shared semantic structure.
– jaron lanier