It is a fact: Google is using alien technology or I have just had a vision from the future.
Let me explain:
One of the Google services I use is Google Alerts to track newly published material in a variety of fields that interest me. As advertised on their page: “some handy uses of Google Alerts include: monitoring a developing news story, keeping current on a competitor or industry, getting the latest on a celebrity or event, keeping tabs on your favorite sports teams”.
Egocentric as it may seem, I also keep an alert on my name. Most results come from articles published or cross-published. Usually it takes days or at best several hours from their publication time, for new web pages to appear.
When I just posted my last article on Flex and saw it online, I visited my Gmail page and clicked on the tag for the Google alerts. Guess what:
In less than 90 seconds from posting to WordPress, Google Alerts had managed to find out about my new post and send me an email about it!!!
How the #@%&*% can you index the web so fast?!?
Social Bookmarks:
Dio Synodinos 
Publish/subscribe notifications model? It becomes more and more popular…
Even if there was a direct agreement between WordPress and Google eg. based on publish/subscribe notifications model, it is still lightning fast. I mean, even if I had posted on Google’s own Blogger, (less than) 90 seconds to load the notification on the AJAX front end of GMail is difficult to grasp :0