A man admitted posing online as a teenage girl to entice boys to send him sexual images and perform sex acts on themselves.
Ethan Brown, who was 16 at the time of the offences, used Facebook and other social media to target the boys that were aged between eight and 17.
Lincolnshire Police and the National Crime Agency worked together and identified 75 victims from across the UK.
Evidence relating to the offences was recovered from his devices. There was also evidence linking his address to the Facebook activity.
A total of 25 prosecutions were brought against Brown, who was charged with Causing and Inciting Children to Child Sexual Exploitation and Possession of Indecent Images Of A Child.
The 20-year-old of Station Road, Waddington, pleaded guilty to the charges after appearing at Lincoln Crown Court on Friday, September 28.
He was bailed and is due to be sentenced on October 26.
Detective Constable Wayne Pilkington, of Lincolnshire Police’s Child Sexual Exploitation Team, led the investigation with support from several specialist departments.
He said: “This was a lengthy and meticulous investigation which took more than three years in total to complete.
“This included interviews with the identified victims, forensic examination of multiple electronic devices and the painstaking review of digital material.
“It also involved a number of lengthy enquiries with law enforcement in America in order to retrieve evidence from Facebook.”