I have a good friend who is incredibly good at wine tasting, so good in fact that he is one of only around three hundred people worldwide who are a Master of Wine.

Give David a wine to taste and he will tell you the grape, the year, the country, the kind of soil and even the wine grower. It's all very entertaining (and he's very polite about anything I serve up at a meal).

There are a lot of people who are experts in a particular field. For many of them, their field is all they know about. Ask them about their interest and they will tell you everything about it. Discuss anything else, and they have little to say.

David is not like that. He is one of those, occasionally annoying, people who know a lot about everything (he is very good to have on your side at Trivial Pursuit.) David's knowledge is so broad; people go to him for a variety of things, from how to rewire your house, to getting a recommendation about a new car.

David is your kind of man if you are a brand. As our Community Igniter research shows, people like David have larger than average personal communities, people go to them for advice and they are more likely than average to try out new products and brands.

Reach out to people like David and they are likely to talk about you or your service or product and people will take notice of them.

But turn this on its head. Some brands have depth when it comes to a particular type of product (say a bank or insurance company), whilst others have breadth (like Tesco - from insurance through to clothes through to mobile phones). Which of these types of brands are people more likely to call upon when they need something? The one that has breadth because it is already likely to have relevance to you...

What does this mean for a brand that has depth and little breadth? It needs to reach out. It needs to find out what kinds of things are important to its target audience.

It may be a brand that only makes chocolate biscuits but what are the kinds of conversations of its target customers that can show it what is important to them? By understanding target customers' needs (outside of the need for chocolate biscuits!) and facilitating those needs, such a brand can make itself relevant so that the next time they are in the supermarket they pick up its chocolate biscuits rather than its competitors.

This approach is especially important for a brand whose products are heavily commoditised. These brands can make them relevant to people by meeting some of their needs outside of its core product - by making itself unique - it can create differentiation from other brands that produce very similar things.

The cafe sector in the UK is a great example of how a few brands have turned what could be a much commoditised product - coffee - into something more. For example, Pret a Manger has created itself as a place for mums to go for relaxation and a chat with each other after the school drop off. Often with quite large spaces, they provide room for pushchairs, as well as magazines, newspapers, Wi-Fi, a reliably good customer service, nutritional information and advice on its foods for mums to be.