Things I learned from Puredata I:
Puredata is a dataflow language. You connect inputs and outputs to boxes that process the flowing data and outputs other flowing data. As data flows it generates more feedback.
Now, a lot of the time, you want data in some place - but you don't want to cascade more actions*. So Puredata has a common abstraction distinguishing between hot and cold input gates. Hot gates trigger an output pulse. Cold gates just deliver data, but don't trigger more activity.
I want this abstraction built into all my communication devices and all my social networks. There are tons of inputs I want to follow, tons of people whose input I care about - but there's a distinction between caring about inputs, as they apply to stuff I am already paying attention to, and caring enough to want to be actively interrupted whenever there is any news at all.
Right now hot or cold is a feature of a particular medium, more than a specific aspect of a particular communication between me and someone or something in a medium.

*It's an energy thing - you can't have loops at all if every pulse must generate more pulses. So a language that always pulses can't be a very sophisticated one.