When it comes to the latest in online advertising and marketing, we can say goodbye to the power of the click and hello to the voices of the most credible digital influencers and the passion-based communities that are highly sought after by digital surfers.

In the new world of digital influencers, it's no longer all about Facebook likes and friends and who's retweeting whom, now it's about calculating digital status. So when Spotify, the music streaming site, launched recently in the US, it gave 100,000 free subscriptions to people with a certain ranking on Klout, a site that tabulates your social credit score based on how influential you are online.

"We've always talked about influencers in media. A Vogue or an Esquire magazine used to talk about owning an influential audience," says Troy Young, president of Say Media, a digital publishing site. "There was always a premium put on people who were taste-makers. Now the difference is that most of those taste-makers are publishers in their own right."

The democratisation of publishing technologies – blogs, Facebook, Twitter etc – has changed the whole advertising and marketing landscape online by opening up the way people think about products and who they listen to when making buying decisions. This is something that Ford Motor Company has been practising since 2008 when it set up a social media unit and started interacting with regular consumers and super bloggers, such as iJustine whose YouTube videos can attract more than 200,000 views.

"We can connect with regular people out there who now have a prominent position and prolific voice; people sit up and take notice [of them]," says Scott Monty, Ford Motor Company's head of social media. "It's not an either-or proposition for us because we have to stay true to our traditional media outlets, but also make room for new media as well."

It's all very exciting, but the challenge for advertisers and marketers is to stand out above the general internet noise and create what the industry calls a value proposition for their brands. In this, Facebook has emerged as a crucial platform for social interaction with 750 million users worldwide, as has Twitter with 250 million. But simply having a Twitter "hashtag", which more easily identifies subjects being discussed, or "liking" something on Facebook are no longer enough.

"We are starting to move away from the mad arms race of [increasing] fans on Facebook," says Oli Newton, head of emerging platforms at Starcom Mediavest.

According to Newton, the number of followers is becoming less significant than the ability to move an audience in a certain direction. "If you have 5 million Twitter followers, that sounds great, but how many are just seeing you and don't do anything with what you post?" he says. "If you have Justin Bieber, Lady Gaga or Stephen Fry saying to do something, then you see a huge movement and that's powerful."

Previously, brands and agencies would create microsites specifically for a media push, but these were often abandoned once the campaign was over, leaving consumers confused. Now it's about continuing the "conversation" with users which may start with a TV advertisement and continues on to the web; for instance, Foster's beer brand uses two plain-speaking Aussies (Brad and Dan) on Twitter and YouTube, posting more content there than ever could be crammed into 30-second TV adverts. Campaigns like this ensure the "message" can be continued and more easily help set up communities of fans of the brand.

Another example is xoJane, an online-only magazine launched in May and aimed at the women's lifestyle audience. Advertisers from Cover Girl to I Can't Believe It's Not Butter all supported this new digital destination created by editor Jane Pratt in collaboration with publisher, Say Media. The xoJane community is growing – interestingly, 30% of traffic comes from referrals from other social media sites.

Pratt sees all her editorial contributors as influencers who interact with their communities, so a fashion writer for xoJane will not just write about the latest trends, but also offer readers one-click shopping opportunities for the items she recommends.

"For me it's about finding strong individual voices and giving them a platform. It's about finding characters that people are going to want to follow," says Pratt.

Every article on the xoJane site can be shared on Facebook or Twitter, and it is sharing that is becoming more important rather than just counting unique user numbers or even "likes". Social media tracking companies such as Klout and Peer Index are standardising the new influencers by ranking how we influence others through our "likes" and tweets and how much other people then amplify what we say. But ways to measure the impact of social media are becoming even more subtle, something that was underlined in a recent Say Media study called Guided by Voices. Among other discoveries, the study found that consumers regarded advertisements as more relevant and trustworthy when they found them on the sites of people who they follow online.

"It's no longer enough to say you need to be social because it's cool. Now it's about the science behind it and how we derive value," says Newton. "What does one interaction actually mean for us and what is the pound sterling value I can put on it?"

The object now is not just to track down the most active people in communities and give them information to post, but to ask these digital influencers to help answer questions about forthcoming products or even something as simple as their opinion on new packaging. "A good influencer is not someone who says just what the brand asks, because that could undermine their value in the community," says Michael Creighton, chief operating officer of Mindshare, part of Group M. Creighton favours a tailored approach to getting influencers on board with products; sending a simple press release is neither enough nor going to hit the right note.

"The biggest thing is to keep listening (to the communities)," adds Creighton. "The minute you say that the social media landscape is set, that's when you miss something. As the brand evolves, it may wish to interact with different communities at different times." There are more challenges around the corner as well. "Facebook and Twitter are developing so quickly that things they couldn't do six months ago they can now, like creating shop fronts and shopping baskets that you can use across Facebook. These things immediately change how you attribute value."