Earned media (free media) refers to favorable publicity garnered via efforts other than advertising, as opposed to paid media, which refers to publicity gained through advertising. Earned media often refers specifically to publicity gained through editorial influence, whereas social media refers to publicity gained through grassroots action, particularly on the Internet.
http://en.wikipedia.org/wiki/Earned_media Brands that want to generate "coverage" in a world where professional and consumer-generated media live side-by-side, they either must "earn" it (PR) or stimulate a conversation (social) based on action, in-action or mis-actions (mistakes). Traditionally, earned media coverage was largely facilitated through public relations campaigns -- professional editors assigned stories to journalists who wrote about something "newsworthy."
While that process is still at work in an ever-expanding media universe, today products and (customer) services that delight consumers by exceeding, or failing, to exceed their expectations earn voluminous word-of-mouth (social media) coverage from armies of bloggers, tweeters, and Facebookers, who magnify the brand message virally.
While earned media has been around since the first campfires, the Internet and social media networks make it much easier to earn media for a brand, product, or oneself. But earning digital media doesn't mean it's free. Instead of paying for media placements (advertising), marketers pay for the time and resources of people who will investigate what's being said about your brand and then engage on your behalf. These can be employees, contractors, agencies, etc.
The resultant "media," social or otherwise, is earned because one cannot buy it (people who blog about products and services should not be compensated by an agency or network). However, influential conversations can be set in motion by brand activated triggers. These can take many forms, from establishing a relationship with bloggers, to sharing news and insights, seeding content, to interacting with people who use your product or service.
Getting earned media right is a tricky balance but the search engine payoff has long-lasting impact in the form of a powerful SEO keyword trail. The key is to figure out how best to participate in the spaces where your brands, products and services are most relevant.
But it's not easy and, in the short term anyway, while highly credible, it may not necessarily be cheaper than paid media. To reap the full benefits of earned media, marketers need to take into account a fast-growing array of platforms like Facebook, MySpace, LinkedIn, YouTube and Twitter as facilitators of earned or social media, not as ends in themselves.
Earned media is widely considered a highly authentic and effective form of communications because it is generally produced in a context that engages rather than interrupts. People generally trust it more than they do paid media, but it is expensive to establish and requires constant vigilance since it lives beyond the marketer's control.
Marketers need to monitor the conversations generated through earned media, analyze sentiment, and participate appropriately. Some people who write or speak about a company's brand are more influential than others (as rated by authority, popularity, followers, link-backs, etc.) so it is crucial that a brand have a long-term strategy to engage influential individuals -- the Alpha bloggers, and their followers.
The resulting "free" coverage is truly earned -- honest, enthusiastic, authentic coverage from influencers reaching deep into their communities. Their content tends to dominate search results via large numbers of articles that can drive up a websites' (brand) organic SEO rating. And unlike paid media, articles and tweets remain online forever, re-appearing in searches, enhancing a brand or company SEO ranking and driving traffic.