Tags. And Power.
You already know tags, they're an easy way to start organizing your content. But power probably needs some explanation.
In short, power is proof-of-work, similar to the way miners hash Bitcoin blocks, but for your content.
Why would you do this?
Consider it a new form of advertising.
The more power you apply to tags, the longer it will take, and the higher your post will appear under them.
Soon you'll be able to purchase more power to shorten the time and increase the proof-of-work.
This is an experiment in next-generation information markets.
Let's see how it evolves...