Influencer marketing is not new. It's been around for many years. Lately it's become a hot topic for marketers - probably because we are realizing how powerful it is, especially as an alternative to traditional advertising that can be expensive and inefficient. More importantly, consumers don't like to be advertised to and marketing messages have less credibility every day. 

What is an influencer?

One of the biggest misconceptions about influencers is that they are someone with a large social media following. This thinking confuses influence with popularity. The act of influencing requires a specific result: a change in thinking or behavior. An influencer, therefore, is someone who has the power to influence the perception of others or gets them to do something different.

When applying this definition to marketers, an influencer is someone who helps other people buy from you. How do they do this? Influencers must have a combination of three key factors: reach, contextual credibility and salesmanship. The higher these three factors, the higher the influence potential of an individual.

• Reach: their ability to deliver a message to a large number of people. This can be the readership of a publication, the audience of a TV host or the number of social followers someone has. Reach is important but insufficient. Those with small reach but high credibility and salesmanship are called micro-influencers.

• Contextual credibility: the level of trust and authority given by the audience based on the influencer's perceived knowledge and expertise on a specific topic. A celebrity chef will have high credibility in recommending meals but low credibility in politics, for example.

• Salesmanship: the presence and communications style that gives the influencer the ability to understand and embrace a particular point of view. There are some people who seem to have an extraordinary power to convince people of their point of view. They have an ability to explain things in convincing ways, are clear with their messages and deliver their points of view with confidence.

Here's how to do influencer marketing right.

The simplest way to work with influencers is to pay them money. Advertisers have used celebrities in their campaigns for decades. Marketers are essentially borrowing their credibility and familiarity to sell a product. This is a tactic that may work, but it is not what we define as influencer marketing -- we call it celebrity endorsements. Consumers know the actor or athlete is getting paid to promote a product, so its effectiveness is limited.

Another way to work with influencers is to borrow their reach. This is how most marketers use influencer marketing today. They look for someone with a lot of Instagram followers and pay them to advertise a product. This is really sponsored advertising and does not maximize influencer marketing opportunities.

The best influencer marketing does not involve financial compensation. Instead, it requires understanding that influencers want to be recognized, have access to information and be the first to know of any news in their space -- they need this to strengthen their influence.

Good influencer marketing is centered on building sincere personal relationships with influencers and sharing useful, unique, exclusive or early information. The good news is that influencers are curious. A marketer with an interesting, useful product should have no problem finding information and knowledge of value to influencers.

The goal of influencer marketing is advocacy.

Influencer marketing should be honest and authentic. An influencer speaks about your product not because they are being paid to do so, but because they want to -- because they find your company interesting and the information useful to their readers.

Therefore, influencer marketing takes time, dedication and focus, and it must be transparent and honest. An influencer will speak about the good and the bad of your products. But they will do in in a way that is far more credible and useful than any ad could do.

When done right, influencer marketing is a multiplier: It leverages the reach, credibility and salesmanship of a community of influencers to advocate your product to consumers, and it results in awareness, improved perception and action.

This article was originaly published on Forbes.com