There are 5 different types of information that could be censored and the rationale varies for each other these:
Moral censorship is the removal of materials that are obscene or otherwise considered morally questionable. Pornography, for example, is often censored under this rationale, especially child pornography, which is illegal and censored in most jurisdictions in the world.
Military censorship is the process of keeping military intelligence and tactics confidential and away from the enemy. This is used to counter espionage, which is the process of gleaning military information.
Political censorship occurs when governments hold back information from their citizens. This is often done to exert control over the populace and prevent free expression that might foment rebellion.
Religious censorship is the means by which any material considered objectionable by a certain faith is removed. This often involves a dominant religion forcing limitations on less prevalent ones. Alternatively, one religion may shun the works of another when they believe the content is not appropriate for their faith. (e.g Lady Gaga - Judas)
Corporate censorship is the process by which editors in corporate media outlets intervene to disrupt the publishing of information that portrays their business or business partners in a negative light, or intervene to prevent alternate offers from reaching public exposure.
Artists want their songs to be played wherever possible so it is common practice to censor particular words, in particular profanities. Some music labels/artist produce these versions themselves in order to fit in with the rules set by various radio and television programs. Some stations may decide to censor them themselves using some of the methods below:
Blanking; when the volume is muted for all or part of the word.
Bleeping; playing a noise, usually a "beep", over all or part of the word.
Resampling; using a like-sounding portion of vocals and music to override the offending word.
Resinging; Replacing a word with a more appropriate word.
Backmasking; taking the offending word and reversing the audio, sometimes the whole audio is reversed (often because it is a home-made job), but more usually only the vocal track is reversed.
Repeating; repeating the word just said before the explicit word was used.
Skipping; deleting the word from the song without a time delay.
Echo; instead of saying a word, it echoes the last word(s) said in the line.
Disc scratching; in hip hop, scratching on the word, making it sound like another word, or make the word said faster or slower.
RoboVoicing; making the word totally non-understandable by overpowering a robovoice effect (usually used as a last resort for home-made jobs).
Distorting; Usually in Hip-Hop, less offensive words such as "sh*t" or else is distorted. It is usually done by shifting down the pitch.
A recent artist that has had her video band from television and Youtube is Rihanna with her song S&M. It was removed due to extensive sexual references and some 'offensive' scenes.
However she is not the first. Below are number of musicians that have had their work censored or edited in some way. (info from wiki - http://en.wikipedia.org/wiki/Censorship )
Robbie Williams only has one censored video, this being Rock DJ.
Robbie Williams - Rock DJ. from Rokkit on Vimeo.
The video showed Williams in an attempt to get noticed by a group of females, first stripping and then tearing chunks of skin and muscle from his body, and caused controversy in the United Kingdom and many other countries. The video was edited by Top of the Pops for its graphic content and many other channels followed suit.
- Fela Kuti, Nigeria - Imprisoned and harassed by Nigerian authorities
- Ferhat Tunc, Turkey - Censored and imprisoned by Turkish authorities
- Gorki Águila, Cuba - Censored by the Cuban Government. Imprisoned August 2003
- Judge Dread, England - The Guinness Book of World Records credits Judge Dread for having the most banned songs of all time on the BBC Radio.
- Madonna, USA - Several videos banned and attempted boycott (usually by religious groups) of several of her concerts (such as her visits in 1990 and 2006 to Rome, her visit in 2006 to Russia, her visits in 2009 to Poland and Bulgaria, etc.). When American television network NBC aired a concert from the artist's Confessions Tour, the part of the show where Madonna stages a crucifixion was censored and replaced with images of orphaned African children (images that were part of the live performance involving the crucifixion, but which were displayed on the on-stage screens behind the singer).
- Marilyn Manson, USA- His release of "(s)AINT" is banned in many countries due to its content including BDSM, cunnilingus and drug use along with masturbation.
- Miguel Angel Estrella, Argentina - Banned, imprisoned and tortured by the Argentine military junta
- Matoub Lounès, Algeria - Assassinated in 1998
- Parissa, Iran - In the Islamic Republic of Iran, female singers often face severe restrictions
- Pink Floyd's album The Wall was banned in South Africa in 1980 after the song was adopted by supporters of a nationwide school boycott protesting racial inequities in education
- Rolling Stones When they were to perform the song "Let's Spend the Night Together", Ed Sullivan famously challenged the Rolling Stones to change the line to "let's spend some time together."
- Thomas Mapfumo, Zimbabwe - Several songs banned by Zimbabwean authorities