In his ‘State of the Union’ address to the Global Marketer Conference, in Sydney, Riley set out the case on why the rise of digital means there was never a "better" or "tougher" time to be in marketing.
Explaining his thinking, Riley said: "Technology gives us the platforms to be part of our consumers’ lives, to earn a space on their newsfeed and the tools to reach, engage and entertain them.
"But it also sets challenges for us. Challenges in understanding all these new platforms and what they can do for us, as well as what they should do for us."
But beyond this, he told delegates, digital technology had changed "our traditional notion of what a brand is and what it means to consumers.
"The truth is, in an age where everything is on show, every brand can have its own Tahrir Square or Wikileak moment," Riley warned.
In this new world, the concept of "local" no longer existed.
Riley said: "Any ill-thought through commercial, promotion, micro-site in Thailand or Peru can come back and bite you in the UK, NZ or Australia. Today, brands are only as strong as their weakest link."
He called on marketers to "remove the walls" between themselves and the corporate and public affairs executives, who deal with NGOs and governments.
"In the outside world their messages blur into one. Social media has made this all possible," he contended.