Hmm, 8M paid M365 Copilot users leaked in August, and at last week's earnings call the number was 15M.

Assuming the leak was accurate, almost doubling usage in 4 months for an enterprise product seems like pretty fast growth?

Its growth trajectory seems to be on par with Teams so far, another enterprise product bundled with their M365 suite, though to be fair Teams was bundled for free: https://www.demandsage.com/microsoft-teams-statistics/