A record chart is a ranking of recorded music according to popularity during a given period of time. Examples of music charts are the Hit parade, Hot 100 or Top 40.

There are lots of different criteria used in different charts used to reflect popularity, commonly: sales of records, cassettes and compact discs; the amount of radio airplay; and (recently) the number of downloads.

Some charts are specific to a particular musical genre and most to a particular geographical location (although download charts are not easily pinned down in this way). The most common period of time covered by a chart is one week with the chart being printed or broadcast at the end of this time. Summary charts for years and decades are then calculated from their component weekly charts. Component charts have become an increasingly important way to measure the commercial success of individual songs.

A chart hit is an extremely popular recording, identified by its inclusion in a chart that uses sales or other criteria to rank popular releases. Chart-topper and related terms (like No. 1 hit, top of the charts, chart hit, and so forth) are widely used in common conversation and in marketing, and are loosely defined. In North America, the weekly charts from Billboard magazine are most often referenced (quite often internationally, as well), particularly the Billboard Hot 100 singles chart and Billboard 200 album chart, although there are many other charts and sources. Because of its value in promoting recording artists and releases, both directly to the consumer, and by encouraging exposure on radio, TV other media, chart positioning has long been a subject of scrutiny and controversy. Chart compilation methodology and data sources vary, ranging from buzz charts based on opinions of various experts and tastemakers, to charts that reflect empirical data such as retail sales. Therefore, a chart-topper may be anything from an "insiders' pick" to a runaway seller.

Susan Magdalane Boyle (born 1 April 1961) is a Scottish singer who came to international public attention when she appeared as a contestant on the TV programme Britain's Got Talent on 11 April 2009, singing "I Dreamed a Dream" from Les Misérables. Her first album was released in November 2009 and debuted as the number one best-selling album on charts around the globe.

Global interest in Boyle was triggered by the contrast between her powerful mezzo-soprano voice and her plain appearance on stage. The juxtaposition of the audience's first impression of her, with the standing ovation she received during and after her performance, led to an international media and Internet response. Within nine days of the audition, videos of Boyle—from the show, various interviews and her 1999 rendition of "Cry Me a River"—had been watched over 100 million times. Her audition video has been viewed on the internet several hundred million times. Despite the sustained media interest she later finished in second place in the final of the show behind dance troupe Diversity.

John Joseph Lydon (born 31 January 1956), also known by the former stage name Johnny Rotten, is a singer-songwriter and television presenter, best known as the lead singer of punk rock band the Sex Pistols from 1975 until 1978, and again for various revivals during the 1990s and 2000s. He is the lead singer of the post-punk band Public Image Ltd, which he founded and fronted from 1978 until 1993, and again from 2009. Throughout his career, Lydon has made controversial or dismissive comments about the royal family and other subjects. There has been a recent revival of a 1980s movement to have Lydon knighted for his achievements with the Sex Pistols. Q Magazine remarked that "somehow he's assumed the status of national treasure."

Lydon's personally crafted image and fashion style led to him being asked to become the singer of the Sex Pistols by their manager, Malcolm McLaren. With the Pistols, he penned singles including "Anarchy in the U.K.", "God Save the Queen" and "Holidays in the Sun", the content of which precipitated the "last and greatest outbreak of pop-based moral pandemonium" in Britain. The band caused nationwide uproar in much of the media, who objected to the content of Lydon’s lyrics, and their antics, which included swearing on live television, in which Steve Jones called Bill Grundy a "fucking rotter". Due to the band's appearance in the media, Lydon was largely seen as the figurehead of the punk movement in the public image although this idea was not widely supported amongst the punk movement itself. Despite the negative reaction that they provoked, they are now regarded as one of the most influential acts in the history of popular music.

Adele Emeli Sandé  /sænˈdeɪ/ san-DAY, (born 10 March 1988) known by her stage name Emeli Sandé, is a Scottish soul and R&B recording artist and songwriter. Sandé first became known to the public eye after she featured on rapper Chipmunk's third single, "Diamond Rings", which gained herself and Chipmunk a first top 10 single on the UK Singles Chart. In 2010, she appeared on Roll Deep star, Wiley's "Never Be Your Woman", which became another top ten hit. Simon Cowell called her "his favourite songwriter at the minute". She has written for a number of artists, including Cher Lloyd, Parade, Susan Boyle, Preeya Kalidas, Leona Lewis, Alesha Dixon, Cheryl Cole, and Tinie Tempah.

In 2010, she signed a publishing deal with EMI Music Publishing. She later announced that Virgin Records had given her a record deal. Sandé released her first solo single "Heaven" in August 2011, which was an instant hit around the globe. Sandé has two number-one singles across the United Kingdom and Ireland with "Read All About It" with Professor Green and "Next to Me". She released Our Version of Events, in February 2012, upon the release the album peaked number one in the UK.

Stefani Joanne Angelina Germanotta (/ˈstɛfəniː dʒʌrməˈnɑːtə/ STE-fə-nee jurr-mə-NAH-tə; born March 28, 1986), known by her stage name Lady Gaga, is an American singer and songwriter. Born and raised in New York City, she primarily studied at the Convent of the Sacred Heart and briefly attended New York University's Tisch School of the Arts before withdrawing to focus on her musical career. She began performing in the rock music scene of Manhattan's Lower East Side, and was signed with Streamline Records by the end of 2007. During her employment as a songwriter for the record company, her vocal abilities captured the attention of recording artist Akon, who signed her to his label Kon Live Distribution.

Lady Gaga came to prominence as a recording artist following the release of her debut album The Fame (2008), which was a critical and commercial success that topped charts around the world and included the international number-one singles "Just Dance" and "Poker Face". After embarking on the The Fame Ball Tour, she followed the album with The Fame Monster (2009), which spawned the worldwide hit singles "Bad Romance", "Telephone" and "Alejandro". The album's success allowed her to embark on the eighteen-month long Monster Ball Tour, which later became one of the highest-grossing concert tours of all time. Her most recent album Born This Way (2011) topped the charts of most major markets and generated more international chart-topping singles, including "Born This Way", "Judas" and "The Edge of Glory". Besides her musical career, she involves herself with humanitarian causes and LGBT activism.