平台 (píng tái) is the general word for 'platform' — both physical (a raised surface) and digital (social media, e-commerce). It is broader than 舞台 (wǔ tái, performance stage) and 站台 (zhàn tái, railway platform), which are specific types of platforms. Unlike 台 (tái), which often appears as a suffix in compound words, 平台 stands alone as a noun.