[narrationbox]

This particular field is difficult. Other than Google (through Search and also its acquisition of Metaweb), no other company has managed to achieve tremendous revenue with a knowledge base product alone. Cyc, Wolfram Alpha, the original IBM Watson (the expert system, not the ML APIs borrowing the brand) are all surviving but not thriving.

[smitty1110]

Don't forget the original knowledge base product - Bloomberg. They still bring in a lot of cash each year, but as a private company we can't get exact amounts.