TikTok monthly active users worldwide

Between 2017 and 2023, the US thrift store market and TikTok's monthly active users both grew, correlating at 0.964 across seven data points. The connection is less spurious than usual: TikTok's thrift haul videos, vintage fashion content, and sustainability influencers directly contributed to the normalization of secondhand shopping among Gen Z. This is one of those correlations where the algorithm literally created the market—TikTok showed young people that thrifting was cool, and the data followed. Seven data points is still too few for statistical confidence, but the mechanism is real enough that the r-value feels almost honest.

The US secondhand market grew from roughly $28 billion to over $50 billion, driven by sustainability consciousness, resale platforms, and the cultural normalization of thrifting. TikTok grew from roughly 100 million to over 1.5 billion MAUs. The connection has a genuine element: TikTok's fashion and sustainability content communities actively promoted secondhand shopping, creating a feedback loop between platform growth and thrift market expansion. However, seven data points cannot prove what anecdote suggests, and the correlation coefficient doesn't know the difference.

Occasionally a spurious correlation contains a genuine mechanism: TikTok's content ecosystem did contribute to thrift market growth. But seven data points cannot prove what anecdote suggests, and the correlation coefficient doesn't know the difference.