After yesterday's rousing paean to creativity at an Ogilvy-organised seminar celebrating the 100th anniversary of the agency's founder, it was the clients' turn for the spotlight in Cannes today. And, while their message was similarly upbeat, the overall tone was notably humble.

Across presentations from Ford and Unilever - two of the biggest clients of all - one message came through, loud and clear: we need to do better. For the US automaker, represented onstage by group vp for global marketing Jim Farley, this process has involved turning more of its marketing over to the customers themselves with a series of initiatives using co-creation and social media. Meanwhile, Unilever ceo Paul Polman said the FMCG giant is trying to convince its worldwide customer base that it can give "great value with great values" - trying to double its overall revenues while reducing its overall environmental impact.

Needless to say, this advice represents something of a one-two punch for advertisers who would prefer to control the conversation as much as possible and cut production costs regardless of green concerns.

Both speakers put the changes their employers are facing firmly in the context of the digital revolution. With the advent of the conversation web, "the whole paradigm as advertisers has changed - to people," Farley said. "The customers and the people should be an equal partner in the way we deliver our messaging." This can be seen in a range of social media-friendly recent campaigns from the firm - guided by its global agency WPP. And some of the low-key, quirky new work has gained viral traction.

"Give your brand up for customers," Farley advised. "It's the most rewarding thing I've ever done."

But this process of giving up and letting go doesn't mean checking out completely from trying to guide the conversation. Instead, the shift in focus towards earned - rather than paid-for - media is great news for PR people. Indeed, Farley now recommends having a "completely integrated" internal PR team to help with the time-consuming process of listening, responding and keeping the customer dialogue going.

Unilever is making similarly profound changes as it tries to grow while embracing sustainability. In his presentation, Polman pointed out that Unilever is facing three major disruptions to the traditional way of doing things: the digital revolution, the ongoing shift in power towards the global south and widespread environmental concerns among consumers - which are as strong in fast-growth economies as they are in the west.

And while Unilever is one of today's biggest companies - its products are used more than 2bn times a day - this might not always be the case. "We're going to have to do things differently if we're to grow in a more volatile, resource-constrained world," Polman said. "There are seismic changes happening."

So it seems that showing a bit of humbleness in the face of change is gaining popularity among big companies. For his part, speaking on a panel with Sir Martin Sorrell and DreamWorks chief Jeffrey Katzenberg, NewsCorp ceo James Murdoch was quick to put the size of his employer into perspective. The fragmentation of consumption patterns represents a "flattening" of the media industry, he said. Now, NewsCorp doesn't just have other newspaper and TV groups for rivals; instead, it competes with "monolithic brands" from tech giants Google and Apple to telcos like Deutsche Telecom. "There are much, much bigger beasts than News Corporation," Murdoch pointed out.

Humble words, certainly. But it's worth noting that News Corp doesn't seem willing to give up its place in the pecking order without a fight. Instead, the media firm will attempt to "compete at scale" with their new rivals.

And the future? News Corp will try to "make ourselves as good at a much bigger scale as we can be," Murdoch said.