Teen pop

Teen pop is a subgenre of pop music that is created, marketed and oriented primarily towards preteens and teenagers. Teen pop incorporates different subgenres of pop music, as well as R&B, dance, electronic, hip hop and rock, while the music of girl groups, boybands and acts like Britney Spears, is sometimes referred to as pure pop. Typical characteristics of teen pop music include autotuned vocals, choreographed dancing, emphasis on visual appeal (photogenic faces, unique body physiques, immaculate hair styles and fashion clothes), lyrics focused on love, relationships, dancing, partying, friendship, puppy love (also known as a "crush") and repeated chorus lines. Its lyrics also incorporate sexual innuendo. Teen pop singers often cultivate an image of a girl next door/boy next door. 
According to AllMusic, teen pop "is essentially dance-pop, pop, and urban ballads" that are marketed to teens, and was conceived in its contemporary form during the late 1980s and 1990s, pointing out the late 1990s as "arguably the style's golden era." About.com's Bill Lamb described teen pop sound as "a simple, straightforward, ultra-catchy melody line [...] The songs may incorporate elements of other pop music genres, but usually they will never be mistaken for anything but mainstream pop. The music is designed for maximum focus on the performer and a direct appeal to listeners." 
In "Crazy About You: Reflections on the Meanings of Contemporary Teen Pop Music" (2002), Phillip Vannini and Scott M. Myers writes that teen pop songs "are targeted to youths presumably unaware and unconcerned with the problems of everyday society. Youths are symbolized as mainly in growing up while having a good time." Some authors deemed teen pop music as "more disposable, less intellectually challenging, more feminine, simpler and more commercially focused than other musical forms." In "Music Scenes: Local, Translocal and Virtual", author Melanie Lowe wrote that teen pop "is marked by a clash of presumed innocence and overt sexuality, a conflict that mirrors the physical and emotional turmoil of its primary target audience and vital fan base: early-adolescent middle-and upper middle-class suburban girls."
History.
20th century.
Teen-oriented popular music had become common by the end of the swing era, in the late 1940s, with Frank Sinatra being an early teen idol. However, it was the early 1960s that became known as the "golden age" for pop teen idols, who included Paul Anka, Frankie Avalon, Fabian, Lulu and Ricky Nelson. During the 1970s, one of the most popular preteen and teen-oriented acts was the Osmonds, where family members Donny and Marie both enjoyed individual success as well as success as a duo apart from the main family (Donny also recorded with his brothers as the Osmonds).
The first major wave of teen pop after the counter-culture of the 1960s and 1970s occurred in the mid to late 1980s, with artists such as Menudo, New Edition, the Jets, Debbie Gibson, Tiffany, Martika, New Kids on the Block and Kylie Minogue. In the early 1990s, teen pop dominated the charts until grunge and gangsta rap crossed over into the mainstream in North America by late 1991. Teen pop remained popular in the United Kingdom with the boy band Take That during this period, until the mid-1990s when Britpop became the next major wave in the UK, eclipsing the style similar to how grunge did in North America.
In 1996, British girl group Spice Girls released their debut single "Wannabe", which made them major pop stars in the UK, as well as in the US the following year. In their wake, other teen pop groups and singers rose to prominence, including Backstreet Boys, NSYNC, 98 Degrees, Hanson, Robyn, All Saints, Destiny's Child, Five, B*Witched, Blaque, LFO, Vitamin C, S Club 7, Westlife, Savage Garden, and M2M. In 1999, the success of teenaged pop singers Britney Spears, Christina Aguilera, Jessica Simpson, and Mandy Moore marked the development of what AllMusic refers to as the "pop Lolita" trend, sparking the short careers of upcoming pop singers such as Willa Ford, Samantha Mumba, Mikaila, Tonya Mitchell, Krystal Harris, Amanda, Brooke Allison, Toya, and Hoku. 
In 2000, 2001, 2002, and to a lesser extent in 2003 artists like Aaron Carter, Swedish group A-Teens, girl groups 3LW, Dream, Eden's Crush, P.Y.T., Play, and boy bands O-Town, B2K, Dream Street were teen pop artists who achieved success. In Latin America, successful singers and bands appealing to tweens and teens were Sandy & Junior, RBD and Rouge.
According to Gayle Ward, the demise of this late 1990s teen pop was due to:
1990s and early 2000s teen pop artists eventually entered hiatuses and semi-retirements (NSYNC, Dream, Destiny's Child) or changed their musical style, including Backstreet Boys, Britney Spears, Christina Aguilera, Jessica Simpson, Mandy Moore, 3LW, and Aaron Carter. Many teen artists starting incorporating genres such as pop rock, contemporary R&B and hip-hop. B2K, a hip hop/pop/R&B group, consisting of four teenage black boys, so they were considered a boy band and was popular across the world, though they were only active from 2000 to 2004. Their style of music was very different than other teenage artists, sounding more mature than the typical boy band, though the members were all in their mid-teenage years as well.
21st century.
In the early and mid-2000s, teenage singers such as Rihanna and Chris Brown achieved success, indicating new relevance of teen-oriented pop music.
The introduction of Canadian singer Justin Bieber, a protégé of Usher, created a resurgence of interest in teen pop, especially of the traditional male teen idol. At the time of his debut album's release, Bieber set records as the only four songs in to the top forty of the "Billboard" Hot 100, the first artist to send all songs from an album in the "Billboard" Hot 100.
In 2005, AKB48 was created to promote idol culture and Japanese pop nationwide and overseas followed by the expansion of sister groups and rival groups locally and internationally over the years. In 2016, SNH48, as AKB48's second international sister group, announced its local Chinese sister groups like BEJ48, GNZ48, SHY48 and CKG48 to integrate idol culture with a Chinese twist.
In 2010, the creation of Ark Music Factory helped contributed a new generation of teen pop artists via the internet, such as Rebecca Black and Jenna Rose, despite major criticism with these artists due to the excessive use of auto-tune. 
As for Japanese teen pop culture, the category of "idol" is playing an important role. Momoiro Clover Z is ranked as number one among female idol groups according to 2013–2017 surveys. In 2011, a Kyary Pamyu Pamyu single "PONPONPON" reached the top ten on Japan's Oricon music chart. The 2012 singles "Candy Candy" and "Fashion Monster" followed this success. In 2016, Babymetal became the highest-charting Japanese band ever in the UK's Official Charts history with the release of their album "Metal Resistance."
By 2020, K-Pop had advanced to the point where it dominated teen pop across the world, with groups such as Red Velvet, Mamamoo, Girl's Generation, Blackpink, Cosmic Girls, Loona, and including the group with the largest following in the world, BTS. Kpop had the fastest growing segment on Spotify, where it increased by more than 2,000% in the last six years, and with more than 120 million playlists.