Carlos Carcach, of Macgregor, had used the website to become friends with the girl and three of her 14-year-old schoolmates, in 2007.

He began seeing one of the girls, a friend of the victim, who had earlier declined to have sex with him, saying she was too young.

He then became more friendly online with the victim, and in September 2007, when the girl was at home from school with the flu, she arranged to meet him in a nearby park.

The two went back to her house and had sex in her bedroom.

She later confessed to another friend in an email sent from her school email account.

The school's email filter identified the email using key words, and the school principal was informed of its contents.

The school then contacted the police and Carcach was charged in November, 2007, with engaging in sexual intercourse with a person under 16.

He pleaded guilty in January this year and was sentenced yesterday in the ACT Supreme Court.

The court heard Carcach, who has a child of his own, had admitted he was aware of the girl's age when he had sex with her, but that the offence had not been planned.

He had also accepted that what he had done was unlawful, but did not fully understand that it had also been harmful to the victim.

In a victim impact statement read out in court, the victim said she had lost the trust of her family and that Carcach's actions would affect her for the rest of her life.

Her mother said the offence had resulted in a breakdown of the girl's relationship with her father, and that the family had had to move homes to escape the bad memories.

She said that she believed her daughter had lost her innocence, and that Carcach would never understand the impact of what he had done until it happened to his own daughter.

In handing down the sentence yesterday, Justice Malcolm Gray said that Carcach's actions had had a significant effect on the girl and her family, and that the law was designed to protect the young and immature.

However he noted Carcach had been opportunistic, rather than predatory, in relation to the victim, and that he had been assessed as being at a low risk of re-offending.

He sentenced him to nine months in prison, fully suspended, and placed him on a two-year good behaviour order.

Carcach will also have to complete an adult sex offenders' program.