Ask HN: Real time PubSub-type notification API service?

I have a bunch of keyword/search terms I want to be notified of if they match anything published in the blogosphere or mainstream news.

Does anyone know of a hosted service API I can use to subscribe to for real time notification of mentions of my keywords?

The traditional media notification space doesn't seem to be API orientated. But with services like Superfeedr and Spinn3r I assumed there would be a number of such services around -- but I can't find any!

Looking for free or paid-for options. Thanks!

(Google News/Blog search doesn't really cut it and isn't API driven - looking for REST or better XMPP orientated service)