CGS stands for Community Guideline Strike. YT stands for YouTube.
Also, Nano's grounded video he put on YouTube was offscreen ( except for the disclaimer he put in the video ) to really prevent a community guideline strike on this video. Please do not post YouTube videos that ripped off terrorist events or make jokes about terrorist events. You cannot authorize it for comedy purposes either. Terrorist events are never comedy and ripping off terrorist events makes fun of the people that were killed in the incident. The main lesson is to never post any violent or graphic content on YouTube ( including people blowing up buildings in any way ) unless it's put into one of the four categories: educational, scientific, artistic, or documentary.