Ask HN: Anybody got more details about Google's percolator?

I've read the article in the register.co.uk which leaves my engineering brain unsatisfied. I see that people registered for USENIX OSDI can access the full text of the paper here : http://www.usenix.org/events/osdi10/tech/ but i'm not registered.

Is there anybody in the HN community who has read this paper, or is familiar with google percolator that could provide a more technical overview of how it works and how it compares to map-reduce?

Impatient minds want to know!