Nielsen SoundScan is an information and sales tracking system created by Mike Fine and Mike Shalett. Soundscan is the official method of tracking sales of music and music video products throughout the United States and Canada. Data is collected weekly and made available every Wednesday to subscribers, which include executives from all facets of record companies, publishing firms, music retailers, independent promoters, film and TV, and artist management. SoundScan is the sales source for the Billboard music charts, making it the official source of sales records in the music industry.

Nielsen SoundScan began tracking sales data for Nielsen since March 1, 1991. The May 25 issue of Billboard published Billboard 200 and Country Album charts based on SoundScan "piece count data," and the first Hot 100 chart to debut with the system was released on November 30, 1991. Previously, Billboard tracked sales by calling stores across the U.S. and asking about sales - a method that was inherently error-prone and open to outright fraud.^{[citation needed]}

Keith L. Clark is a Professor of Computer Science at Imperial College London, England. He has lectured in both mathematics and computer science. Since 1979 he has had a tenured position in the Department of Computing, Imperial College London, where he has been Professor of Computational Logic since 1987. Between 1987 and 1995 he was also Visiting Professor at Uppsala University. He is currently a Visiting Professor at BTH (since 1997), and at the University of Queensland (since 1998). In 1980 he co-founded an Imperial College spin-off company, Logic Programming Associates, to develop and market Prolog systems for micro-computers (micro-Prolog) and to provide consultancy on expert systems and rule based applications.

His key contributions have been in the field of logic programming. His 1978 paper on negation as failure was arguably the first formalisation of a non-monotonic logic. His 1981 paper on a relational language for parallel programming introduced concurrent logic programming.

Recently he has been working on the April and Go! programming languages and their application to agent programming.

David Darnell Brown (born March 15, 1981), also known as Young Buck, is an American Southern rapper. Buck is a former member of the New York City hip hop group G-Unit and is still signed to G-Unit Records. He currently resides as president of his own record label, Ca$hville Records.

Around the age of twelve he was making rap songs and rolling up blunts with dean mclees and kyle stewart . he was mostly found around the spruce way area , Brown began rapping because he was inspired by a Miami friend named Clay Cole. Jealous of his friend's talent, he wanted to beat him no matter what he had to give up. At the same time Clay Cole moved to Tallahassee, Fla., Brown began recording in a real studio. Shortly thereafter, he was given an opportunity to perform for Brian "Baby" Williams, co-founder of Cash Money Records. After several years on and off of Cash Money Records, Brown and fellow rapper Juvenile decided to leave the label for good in 2000 and go to UTP Records, where Brown stayed until 2003. One of his early appearances was on the song "Memphis," where he was featured along with Three 6 Mafia, Project Pat, and other southern rappers. His deal with UTP later led to a meeting with New York rapper 50 Cent, who later signed him to G-Unit Records, under Interscope Records.

Curtis James Jackson III (born July 6, 1975), better known by his stage name 50 Cent, is an American rapper, entrepreneur, investor, record producer, and actor. He rose to fame with the release of his albums Get Rich or Die Tryin' (2003) and The Massacre (2005). His album Get Rich or Die Tryin' has been certified eight times platinum by the RIAA.

Born in the South Jamaica of Queens, New York City, Jackson began drug dealing at the age of twelve during the 1980s crack epidemic. After leaving drug dealing to pursue a rap career, he was shot at and struck by nine bullets during an incident in 2000. After releasing his album Guess Who's Back? in 2002, Jackson was discovered by rapper Eminem and signed to Interscope Records. With the help of Eminem and Dr. Dre, who produced his first major commercial successes, Jackson became one of the world's highest selling rappers. In 2003, he founded the record label G-Unit Records, which signed several successful rappers such as Young Buck, Lloyd Banks, and Tony Yayo.

Jonathan Smith (born January 27, 1971), better known by his stage name Lil Jon, is an American rapper, music producer, entrepreneur, and international DJ who was a member of the group Lil Jon & The East Side Boyz. Lil Jon formed the group in 1997, and the group released several albums between then and 2004. He then went solo and released a new album in 2010 called Crunk Rock.

Lil' Jon was born and raised in Atlanta, Georgia. He graduated from Frederick Douglass High School.

After working as a DJ for Atlanta night clubs, he started working for So So Def Recordings between 1993 and 2000. The group signed to the Atlanta-based Mirror Image Records and were distributed by Ichiban Records. In 1997, Lil' Jon & the East Side Boyz debuted with Get Crunk, Who U Wit: Da Album. It included singles "Who U Wit?" and "Shawty Freak a Lil' Sumthin'", the latter of which came out in 1998. Both singles charted on the Billboard Hot R&B/Hip-Hop Songs chart at No. 70 and No. 62 respectively. In 2000 Jon took part in starting up his own label BME Recordings and signed a distribution agreement with Norcross, Georgia based Southern Music Distribution. There he released his break through album titled We Still Crunk. Among the tracks on that project was the hit single "I Like Dem Girlz", which reached No. 55 on the R&B chart and No. 3 on the Hot Rap Tracks chart.