They are already monetizing their data. DataSift is one of their key official partners [0].

[0] http://datasift.com/

That was my initial thoughts. Might this be a potential way to monetize twitter finally?

Could you elaborate please? Are you refering to the "early access" to trending topics, or restricting limits on API?

Funnily enough, Twitter could already sell 'early access' without any new algorithms. Just time shift the availability of results based on payment status. So for £100, see things that are guaranteed to be trending next hour, because they're technically trending now, but we're withholding it.