Ever since the 1970s, musicians and bands have been using screen printed clothes as a primary place for promotion. Printed sweatshirts and embroidered fleeces bearing a musicians' branding not only enables fans to show their devotion to the music of their choice, but also provides an important income stream for the band or record label. This is because printed t-shirts and printed polo shirts can provide the perfect platform for a range of designs and slogans, which makes them ideal for the job.

During October, record label EMI Music Publishing announced a new partnership with Sainbury's Tu Clothing. This involves lyrics from some of the most popular songs ever created being emblazoned on printed ladies t-shirts and printed sweatshirts. Music lovers can therefore bear lyrics from pop songs such as Wild Thing by the Troggs and My Girl by the Temptations on their chests. The collection is also part of a wider initiative by the record label to produce products bearing song lyrics, which has so far included board games, posters and greeting cards.

However, music-based screen printed clothes can also be used to generate money for good causes. The Yellow Bird Project is based in Montreal, Canada, and is devoted to recruiting musicians to design their own printed t-shirts. All proceeds from the sale of these printed clothes will go to charities which the musicians have personally selected. This means that fans get a limited edition item of printed clothing which has been designed by their favourite group, while also helping a worthwhile cause at the same time.

Recent bands to participate in the scheme include indie rock group Broken Social Scene, who have created a navy ladies digitally printed t-shirt with Hope for Truth written on it. The group also selected environmental justice organisation Lake Ontario Waterfront as their chosen charity. The Shins opted for Nature Conservancy to benefit from their grey shirt with the image of a man, while British band the Magic Numbers chose the Aids Society to receive the sale proceeds from their embroidered rugby and drill shirts.

A total of 19 bands have designed printed sweatshirts for the project. New acts to get involved in the scheme include Justin Vernon's folk group Bon Iver, who opted for a grey printed t-shirt with an unusual red motif which has been designed by UK artist Eleanor Rudge. All proceeds from the sale of these embroidered polo shirts will go to the women's shelter Interval House. Finally, Canadian rapper K-OS has designed a mint green digitally printed shirt bearing an image of an African woman in support of children's charity ONEXONE.

Whether it is for a good cause or just for promotion, branded screen printed clothing is an important part of musical entertainment. This is because it offers the perfect place for fans of the band or artist to show their allegiance to the music. It can also generate an important income for both established and aspiring musicians, as well as potentially provide funds for good causes too. Overall, the partnership of music and printed clothing always strikes the right note.

Relatives of Jean Charles de Menezes this week wore screen printed clothes as a protest while attending the inquest into his death. The Brazilian was shot in 2005 by tactical police officers after being mistaken for a terrorist. Relatives of the man wore printed t-shirts bearing the slogans Unlawful killing Verdict and Your Legal Right to Decide in an effort to sway the coroner's verdict at the inquest. What this certainly demonstrated is that screen printed clothes are the perfect platform to stage a protest and get your point across.

The history or printed clothing being used as a means of protest goes back a long way. Teenagers have been wearing printed shirts bearing the image of Cuban Revolutionary leader Che Guevara since the 1970s. The same popularity in printed sweatshirts is true for a variety of political icons, including Martin Luther King and, most recently, Barack Obama. Just as printed t-shirts are important as a fashion statement, they are also the ideal place to show off people's beliefs and values.

Liverpool football club this week escaped sanctions from the Football Association (FA) for a screen printed clothing protest staged before a premiership game. Players from the club wore printed polo shirts bearing the slogan Free Michael Now in support of fan Michael Shields. Mr Shields was sentenced to ten years in jail for attacking a Bulgarian waiter in Varna during a holiday following Liverpool's victory in the 2005 Champions League final. Despite another man since admitting to the crime, Mr Shields is currently being held in jail in Cumbria because the other man will not travel to Bulgaria for questioning.

According to the Los Angeles Times, a crowd of almost 7,500 people converged last month in the civic centre of the city to protest against California's Proposition 8, which would ban gay marriage in the state. Members of the crowd wore printed rugby and drill shirts with Milk emblazoned on the front. This is a direct reference to Harry Milk, the states' first gay campaigner who was assassinated 30 years ago.

Similarly, students from the University of Manchester recently targeted the Royal Bank of Scotland with a climate change protest. The group donned yellow printed clothes bearing the slogan Leave It in the Ground to criticise the bank's alleged involvement with the fossil fuel industry. The group staged the peaceful protest, which included a technique called silent theatre, at a recruitment evening hosted by the bank.

Renowned environmentalist Robbie Gillett led the protest and he told Student Direct: "The silent theatre technique is a really interesting way of getting your message across because it sidesteps people's preconceptions of what and who 'protesters' look like and say. Activists in Manchester are developing a broad repertoire of protest tactics. It's not just about marches and megaphones anymore."

However, it should always be noted that wearing provocative slogans emblazoned across your chest will always entice a wide variety of reactions; often less than positive ones. Three men in Singapore were recently sent to jail for wearing printed shirts bearing the image of kangaroos in judge's robes at a hearing in front of the country's Supreme Court. The men were convicted of contempt of court for undermining the justice system. Despite this, whether your cause may be serious or trivial, it is certainly clear that screen printed clothes are the perfect platform to tell it to the world.

Screen printed clothing could be the key to ensuring that online content remains free but also delivers an income for its creators. Wired magazine suggests that creative people and groups are increasingly harnessing the so-called 't-shirt economy' in which the sale of printed clothing helps to provide an income stream to compliment free online content.

During 2003, Burnie Burns alongside three of his friends launched Red Vs Blue, which is a humorous animated series set in the world of video game Halo. The show became a hit with almost a million people downloading the free episodes every week. After deciding that they wanted to leave their paid jobs and concentrate solely on the show, Burns and his friends decided that printed clothing was the way to back their creativity with sound financial sense.

The sale of branded printed sweatshirts and printed polo shirts is important in this instance because charging for online content is generally a problematic process. Even a small fee for users to view an episode of Red Vs Blue could prove a turn-off for both new and old fans of the series. Therefore, creative teams using online media have instead learnt to look elsewhere for ways to make money.

Branded printed clothing can generate an income from fans who want to support the videos, while also allowing the content to remain free. This means that it has a greater dynamism to circulate around the internet and accrue a larger number of fans. If the content carriers a charge, then it may stall the show before it reaches the stage where branded printed clothing can really provide a sustainable income. Furthermore, printed t-shirts can also act as marketing tool to spread the word about the show to other people.

According to figures compiled by clothing trade publication Impressions, around $40 billion (£26.1 billion) is spent each year in the US alone on branded apparel. The printed clothing industry incorporates a wide variety of entities; ranging from bedroom businesses to multinational corporate companies. New York photographer David Friedman has a printed clothing business which produces four humorous designs each year featuring blurred, fictional corporate branding. This brings a reasonable enough income to cover his cost and provide a small profit.

At the other end of the scale, Busted Tees has predicted that it will sell 350,000 printed t-shirts by the close of 2008 and clear a 20 per cent profit. Alternatively, Cafe Press or Zazzle both enable artists, musicians and creative types to select a range of designs but not have to pay any money until they make a profit on their first printed t-shirt. Fred Durham, co-founder of CafePress, told Wired: "When you drive the risk to zero, you really open the floodgates."

The t-shirt economy can also help with various entertainment acts as consumers are often equally reluctant to pay a charge to listen to a podcast or read a blog. Therefore branded clothing, such as printed ladies t-shirts and polo shirts, can generate a viable income to sustain creative endeavours. Whether creating music, art, film or just entertainment, printed clothing holds the key to sustainable success.