James Haig, 24, preyed on the teenager online after she had a difficult time at school. He arranged to meet her and took her back to his dad's house where he raped her.
The girl kept the attack a secret for three years, but wrote about it in her diary. Her mum became worried about her behaviour and read her diary, uncovering the horrific attack.
Haig, of Ashington, Northumberland, denied rape but was jailed for six years by Newcastle Crown Court and ordered to sign the sex offenders' register for life. He was also banned from ever having contact with children.
The teen met Haig on the social networking site, Tagged.com, which says it is 'the social networking site for meeting new people'. After he appeared caring and supportive with her problems at school, the pair met up, and went to Haig's father's house to watch a DVD. He then raped her, ignoring her pleas for him to stop.
Jonathan Devlin for the prosecution said the attack was only uncovered when the girl's mum flicked through her diary to try and help when she became concerned for her daughter's welfare.
"The girl's mother read her diary and there was an entry relating to this incident. She raised the subject with her daughter and she said she had been raped.
"She said she didn't say anything at first in case she was blamed, having gone to meet him in the first place."
Haig had already been convicted for inciting a 15-year-old to engage in sexual activity on a webcam and had been cautioned for having sex with another teenager of the same age.
Detective Inspector Paul Race from Northumbria Police's rape investigation team said:
"We hope this sentence will give some closure to the victim and her family. It has been a very traumatic ordeal. I urge any parent or guardian to be vigilant with your children's internet access and usage.
"The internet and social sites are in effect faceless, and unbeknown to some youngsters there are people out there who will target and abuse their innocence.
"This isn't just about computers and laptops any more. The smartphone or tablet you may have bought your kids this Christmas is likely to have access to the internet and social outlets.
"Make sure you are able to maintain their safety on these sorts of devices too."
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