互动 has become extremely common in the digital age. On Chinese social media (Weibo, Douyin, Bilibili), 互动 means likes, comments, shares — any engagement. 互动率 (hùdònglǜ) is 'engagement rate.'
grammar
互动 can be a verb (我们来互动一下, let's interact) or a noun (增加互动, increase interaction). Adding 性 makes it an adjective: 互动性 (interactivity).
