In August, a court found the boyfriend, hairdresser Choi Jong-bum, guilty of assault and of threatening to circulate the sex video, although not of filming without her consent. He has denied the allegations and has filed an appeal.
After Goo's case hit the headlines, more than 275,000 people signed an online petition demanding that the presidential office implement stronger punishment for revenge-porn offenders.
Goo's last post on Instagram, published Saturday, was a photograph of herself in bed with the caption: "Good night."
Last month, Sulli was found dead in her apartment, with an autopsy later concluding that there was evidence that she may have committed suicide. In an Instagram live session the day after Sulli's death, a tearful Goo spoke about her friend and pledged to work harder and live harder herself.
Sulli's death highlighted the huge pressures on K-pop stars, partly exerted by demanding fans, and the lack of mental health support in a country with the highest suicide rate among rich nations.
Both women had their private lives intensely examined in public and were the subject of hateful online comments, in an industry where female K-pop singers are not supposed to date or even live real lives but instead conform to rigid norms.
But the death of Goo also highlights the scourge of revenge porn, as well as an epidemic of what is known as molka in South Korea, where women are covertly filmed with spy cameras and footage uploaded to websites.
Sulli was outspoken about her mental health issues and shared her experiences dealing with malicious online comments.
Suicide is the leading cause of death for South Koreans between the ages of 10 and 39, according to government statistics.
WHERE TO GET HELP:
If you are worried about your or someone else's mental health, the best place to get help is your GP or local mental health provider. However, if you or someone else is in danger or endangering others, call police immediately on 111.
OR IF YOU NEED TO TALK TO SOMEONE ELSE:
• DEPRESSION HELPLINE: 0800 111 757
• KIDSLINE: 0800 543 754 (available 24/7)
• LIFELINE: 0800 543 354 or 09 5222 999 within Auckland (24/7)
• NEED TO TALK? Free call or text 1737 (24/7)
• SAMARITANS – 0800 726 666
• SUICIDE CRISIS HELPLINE: 0508 828 865 (24/7)
• WHATSUP: 0800 942 8787 (1pm to 11pm)
• YOUTHLINE: 0800 376 633, free text 234 or email talk@youthline.co.nz
There are lots of places to get support. For others, click here.