“If you’re in advertising, you’d better learn to speak digital, because that’s the way the world is going.”

Those words come from Josh Bernoff’s Groundswell blog today, summing up Forrester Research’s just completed five-year interactive marketing forecast. Over 70% of the marketers they surveyed expected the effectiveness of channels like created social media, online video, and mobile marketing to increase, while the effectiveness of direct mail, television, magazines, outdoor, newspapers, and radio would stay the same or decrease.

They expect digital marketing to grow to about 21%  of advertising spend in five years, while overall budgets are declining. And of all aspects of digital marketing, social media is the area expected to show the greatest growth, growing from $716 million this year to $3 billion in five years, between social networking campaigns and agency fees. (And this doesn’t include ads on social networks, because those are considered display ads.)

What does all this mean for you, dear friends? Time to get your digital on. Old school just won’t cut it for much longer.

We leave you with this eulogy from, well, a social media site.

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