Characteristics of common graffiti

Some of the most common styles of graffiti have their own names. A "tag" is the most basic writing of an artist's name, it is simply a handstyle. A graffiti writer's tag is his or her personalized signature. Tagging is often the example given when opponents of graffiti refer to any acts of handstyle graffiti writing (it is by far the most common form of graffiti). Tags can contain subtle and sometimes cryptic messages, and might incorporate the artist's crew initials or other letters. One form of tagging known as "pissing" is the act of taking a refillable fire extinguisher and replacing the contents inside with paint, allowing for tags as high as around 20 feet. Aiming and keeping a handstyle steady in this form of tagging is very difficult, usually coming out wavy and sloppy.
Another form is the "throw-up", also known as a "bombing" which is normally painted very quickly with two or three colors, sacrificing aesthetics for speed. Throw-ups can also be outlined on a surface with one color. A "piece" is a more elaborate representation of the artist's name, incorporating more stylized letters, usually incorporating a much larger range of colors. This of course is more time consuming and increases the likelihood of the artist getting caught. A "blockbuster" or "roller" is a large piece, almost always done in a block shaped style, done simply to cover a large area solidly with two contrasting colours, sometimes with the whole purpose of blocking other writers from painting on the same wall. These are usually accomplished with extended paint rollers and gallons of cheap exterior paint.

A more complex style is "wildstyle", a form of graffiti usually involving interlocking letters and connecting points. These pieces are often harder to read by non-graffiti artists as the letters merge into one another in an often undecipherable manner. Some artists also use stickers as a quick way to catch ups. While certain critics from within graffiti culture consider this lazy, stickers can be quite detailed in their own right, and are often used in conjunction with other materials. Sticker tags are commonly done on blank postage stickers, as these can be easily acquired with no cost on the writers part.
Many graffiti artists believe that doing complex pieces involves too great an investment of time to justify the practice. Doing a piece can take (depending on experience and size) 30 minutes to months on end, as was the case for Saber MSK while working on the worlds largest graffiti piece on the LA river. Another graffiti artist can go over a piece in a matter of minutes with a simple throw up. This was exemplified by the writer "CAP" in the documentary Style Wars, who, other writers complain, ruins pieces with his quick throw ups. This became known as "capping" and is often done when there is "beef", conflict between writers.
Theories on the use of graffiti by avant-garde artists have a history dating back at least to the Scandinavian Institute of Comparative Vandalism in 1961. Many contemporary analysts and even art critics have begun to see artistic value in some graffiti and to recognize it as a form of public art. According to many art researchers, particularly in the Netherlands and in Los Angeles, that type of public art is, in fact an effective tool of social emancipation or in the achievement of a political goal.
The murals of Belfast and of Los Angeles offer another example of official recognition. In times of conflict, such murals have offered a means of communication and self-expression for members of these socially, ethnically and/or racially divided communities, and have proven themselves as effective tools in establishing dialog and thus of addressing cleavages in the long run. The Berlin Wall was also extensively covered by Graffiti reflecting social pressures relating to the oppressive Soviet rule over the GDR.
 Many artists involved with Graffiti also are concerned with the similar activity of Stencilling. Essentially, this entails stenciling a print of one or more colors using spray-paint. Recognised while exhibiting and publishing several of her coloured stencils and paintings portraying the ethnic conflict in Sri Lanka and urban Britain in the early 2000s, graffiti artist Mathangi Arulpragasam a.k.a. M.I.A. has also become known for integrating her imagery of political violence into her music videos for singles "Galang" and "Bucky Done Gun", and her cover art. Stickers of her artwork also often appear around places such as London in Brick Lane, stuck to lamp posts and street signs, having herself become a muse for other graffiti artists/painters worldwide in cities including Seville.^[36] Graffiti artist John Fekner, called "caption writer to the urban environment, adman for the opposition" by writer Lucy Lippard,^[37] was involved in direct art interventions within New York City's decaying urban environment in the mid-seventies through the eighties. Fekner is known for his word installations targeting social and political issues, stenciled on buildings throughout New York.
http://en.wikipedia.org/wiki/Graffiti