Allow me to go against an important prejudice; there is more to Street Art than graffiti.
The first reason is technical in nature; installations, stencils, stickers, all these techniques are used in street art, whose definition cannot be reduced to “improvised drawing with spray paint”.
The second reason is conceptual; Street Art is a direct relative of Avant-Garde movements and a successful experiment of contemporary art, since its intention is in now way dictated by urban vandalism. Street Art is strongly conceptual, based on an aesthetic that is, if not always revolutionary, certainly ironic; the message prevails on the form.
And it could be no other way, considering the choice to transform graphical expression to something similar to a performance; the quick and hidden gesture finalized to a theatrical and completely public result reminds us of the long history of anonymous satire on society, power and the powerful. Street works of art are naturally viral since they voluntarily jump in the crowd, accepting the will of the public to delete, modify, vandalize and copy them at will. Although it certainly is not art of the people, since it is individualistic in its creation, it still certainly is art for the people, since the street is the chosen destination for the work of art. The street, as the chosen location, actually contributes to provide understanding to what is graphically described – here are some examples.
Banksy is certainly the artist that in the recent years has best represented (in a completely anonymous way), the voice of the movement; his documentary Exit through the Gift Shop is a small masterpiece in itself.
If I had to conclude with the element I most love of Street Art, I would say I find simply wonderful the idea of liberating art from its conventional spaces (museums, galleries, etc.) to transport it in everyday life; generally speaking, Street Art is probably the most original element in the artistic discussion of the last 20/30 years.