Very cool. I hope they start to explore the implications of indexing a trusted source at some point. Google ignores most metadata on your pages because for all it knows you're using that metadata to game the system. With site search that's not an issue, so the search engine could look for certain metadata on the pages it crawls, from author to importance/boost to activating keywords. The interface currently allows you to do some of this (e.g. reordering), but being able to guide the indexer from within your CMS would be even nicer.

Also +1: more clarity on pricing, please.