[arnabdotorg]

The key value is not as much in the data itself, as much as the _timeliness_ of the data. Access to the halfhose allows you to answer a _very_ valuable question:

"What's happening right now?"

This question is worth a lot of money, and something that doesn't have a good algorithmic solution(e.g. Google News.) Twitter is probably the only company that has a privacy-compliant solution to this, hence making it a very monetizable product.

[djb_hackernews]

But Twitter already provides an API for that. You can ask what are the current top 10 trending topics at any time.