Estimate the total number of annual hotel bookings made globally on Expedia.

To estimate the total number of annual hotel bookings on Expedia, we can break down the problem by considering the global population and then segmenting it by Expedia's market penetration and booking habits.

1. Global Population: Start with the world population (approximately 8 billion).
2. Internet Penetration: Estimate the percentage of the global population with internet access (around 60-70%).
3. Online Travel Agency (OTA) Users: From the internet-connected population, estimate the percentage who use OTAs for travel bookings (e.g., 20-30%).
4. Expedia's Market Share: Within the OTA user segment, estimate Expedia's market share. This will vary by region, but a global average might be 15-25%.
5. Booking Frequency: Estimate how many hotel bookings (nights) a typical Expedia user makes per year. This could range from 1-3 bookings per year on average.
6. Calculation: Multiply these figures together: (Global Population) * (Internet Penetration) * (OTA Users) * (Expedia Market Share) * (Booking Frequency per User).

For example: 8 billion * 0.65 (internet users) * 0.25 (OTA users) * 0.20 (Expedia share) * 1.5 (bookings/user/year) = 195 million bookings per year.

This is a rough estimate, and refining it would require more specific data on regional market shares, user demographics, and booking patterns.