ok, i'm highlighting two awesome pieces of information in that specific blogpost. both of them aren't new but this is the first time they were ever officially confirmed by google.

  Google begins indexing yummy-sundae.html and, as a part of 
  this process, decides to attempt to render the page to  
  better understand its content and/or generate the Instant 
  Preview.

this is the first time ever that google confirms that they are internally rendering the page - not only for preview purposes - but also for indexing purposes.

  >Remember to include important content (i.e., the content you’d like 
  >indexed) as text, visible directly on the page and without 
  >requiring user-action to display. Most search engines are text-
  >based and generally work best with text-based content. We’re always 
  >improving our ability to crawl and index content published in a 
  >variety of ways, but it remains a good practice to use text for 
  >important information.

first time ever they advise - directly - against "user action dependent hidden content"