A look at Tree Hole Rescue, which uses AI to detect suicidal messages on Weibo, and has rescued ~700 people who attempted suicide in China in the last 18 months (Yitsing Wang/BBC)

Yitsing Wang / BBC:
A look at Tree Hole Rescue, which uses AI to detect suicidal messages on Weibo, and has rescued ~700 people who attempted suicide in China in the last 18 months  —  Li Fan, a 21-year-old student, attempted suicide after posting a brief message on the Chinese Twitter-like platform Weibo just after Valentine's Day.