知乎，让每一次点击都充满意义 —— 欢迎来到知乎，发现问题背后的世界。 In 1951, the British Board of Movie Censors launched the X certification to point a film was "particularly graphic." However this originally referred to violence and lousy language and sex, "X-rated" was co-opted because of the porn industry and is now shorthand for sexually explicit material. https://coingenius.news/10-year-bitcoin-holdings-grow-faster-than-daily-issuance-marking-scarcity-signal-after-2024-halving/