This paper explores the lexical-pragmatic changes of gratitude verb constructions on social media platforms. Gratitude constructions display a wide range of formal innovations on social media platforms, encompassing both novel lexical and phrasal constructions. These constructions have become highly conventionalized and are now used as fixed idioms. Two kinds of pragmatic changes are observed: positive and negative implicatures. The former category conveys positive emotions such as appreciation, delight, and teasing, which are mainly motivated by the causal chain of thanking events. The latter subtype denotes negative feelings like speechlessness, unhappiness, and anger, which are motivated by the pragmatic shift of xiè-xiè 谢谢 ‘thanks’ in daily communication and reinforced by the online keyword censorship. Driven by the context collapse in social media, the pragmatic functions of gratitude constructions have shifted from positive to negative. This paper aims to shed light on lexical-pragmatic studies and Internet language changes.