There's a lot of very valuable information in this thread.
What's important to remember is that Google NEVER wants to make it so that marketers and SEO professionals can't do their jobs.
What's Google wants is to make sure that when search engine marketers do their job, they're doing it in a way that actively makes the Internet a BETTER place.
This means that search engine marketers frivolously populating the web with a ton of barely-relevant backlinks won't win the game anymore (this has been the case for years, now).
This means that frivolous guest blog posting won't cut the mustard anymore.
What this continues to mean, with just about every step Google takes in terms of its SEO and raking policies, is that Google wants to make sure that the BEST content is getting the most attention.
Content that is thoughtful, original, relevant, and is shared and/or pointed to by sources of high repute will be pushed to the top of the search rankings.