Happy to see my alma mater Efficient Frontier represented (via their acquisition earlier this year of Context Optional).
One thing I'd note from the AdWords Blog article:
"We also recognize that some businesses use social media management companies to manage their presence across multiple social networks." - Google's phrasing implies those using 3rd party management companies are the exception and not the rule. It's open to debate, but my read of social media is that most big FB advertisers absolutely use 3rd parties.