三连 is the signature engagement action on
哔哩哔哩 (Bilibili / B
站):
点赞 (like) +
投币 (toss a coin, B
站's micro-tip) +
收藏 (favorite). Originally users would press all three in sequence; B
站 later added a long-press shortcut that triggers all three at once, which itself is called
一键三连. Saying
一键三连 /
三连 in a video outro is the equivalent of 'like, comment, and subscribe.'
