Millennials are often seen to as the Holy Grail of marketing partly because of their disposal income and partly because their tech-savvy means they can be reached in so many ways. The biggest mistake brands make, however, is to think they reach Millennials through technology.

According to this new survey from the Pivot Center, the answer is cause marketing. Almost two-thirds of the respondents to the poll agreed that green and socially conscious initiatives were one of the top factors that differentiated Millennials from other demographic and psychographic groups.

The fastest way to reach Millennials is not through twitter, Facebook or any one of the location-based services, but through their hearts and minds by adding meaning to their lives.

It’s easy to dismiss this assertion as obvious or redundant. But judging by the number of companies whose social media workshops and seminars focus solely on the  technology rather than on the engagement it enables, it seems that much of the marketing world is mistaking the map for the landscape.

What’s critical is how these technologies connect shared values between brands and Millennials. Of course quantifying this isn’t easy. Effective formulas to measure return on investment (ROI) on social media campaigns for brands are just emerging. Measuring a meeting of hearts and minds is even harder.

Yet brands that fail to re-frame their thinking around relationships rather than returns will never understand or emulate the success of the Pepsi Refresh Project, Nike Livestrong/Chalkbot campaign or Ford’s ‘Invisible People’ initiative.

Rather than focus on what brands can sell using social media, companies must focus on how they can serve their community by investing in what Millennials care about. Do that and brands will not only be relevant to their lives but their community will work with them to achieve common goals.

That doesn’t mean brands have to be serious or sanctimonious all the time. Look at Ben Stiller’s Stillerstrong or the new comedy campaign for Malaria No More. Seen with an open mind, cause marketing represents a fantastic opportunity for brands to breath fresh air into their own voices and earn customer loyalty all over again. In short, brands need to “Wake Up, Lighten Up and Step Up” to the contribution they could be making to social issues and their own brands. (I just put it that way ’cause it seemed fun.)

It says something about past marketing strategies that we must now make a case for the simple proposition that brands must do something good for their communities for customers to like them. Report after report tells us that consumers, including Millennials, want brands to build a better world, not just better widgets. Those that do will profit (in every sense of the word) exponentially, and those that don’t will continue to stare at their number of twitter followers, Facebook fans, ROI formulas or P&L breakdowns looking for answers that just aren’t there.

Do you think brands are finally waking up to their role as contributors? Or do you think companies only ever make such efforts disingenuously?