The sort of reputations they build aren't just about breaking the law or putting oneself at risk to put up the art, they're about creating thoughtful, elegant, interesting images and messages. They're about having enough passion behind a communication that they'll do it for free, without any goal other than to make people think.
We see vague attempts at this style of branding in the advertising and design for some urban and teen brands. While a traditional marketing person would first think to try and sign up these graffiti artists as designers for their ads and websites, that would be missing the point. It's not the fonts or the layouts, it's the meaning behind the communications. Artists like Banksy are winning credibility by being publicly curious, playful and questioning. His brand is earnest, raw and effortless. If it's cool, it's not because he's trying.
Banksy wrote the following advice for aspiring stencil artists, but it could clearly apply to brands in general:
'The time of getting fame for your name on its own is over. Artwork that is only about wanting to be famous will never make you famous. Any fame is a bi-product of making something that means something. You don't go to a restaurant and order a meal because you want to have a shit.'
http://www.banksy.co.uk/
more Banksy art
Guardian article
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yea..i just really wish other people could see it as art ,as a political message . but they see it as scum..