I see around 80% of videos on X (Twitter) to be from TikTok originally. Probably because TikTok allows you to save - and so to spread - videos you like but X doesn’t.
Heh, this is kind of complicated. It was Dorsey's initiative. The project's goal was to produce a technology that Twitter could move to. However, nobody on the team was from Twitter.
That and people posting screenshots of their own tweets...