Estimate the total storage used by Dropbox.

To estimate Dropbox's total storage, we need to consider the number of users and their respective storage usage. We'll assume a worldwide scope and all user segments.

1. User Segmentation: Divide users into tiers based on their likely storage needs:

   • Free Users (80%): Assume a small percentage of their 2GB free tier is used, say 1GB per user.
   • Paid Users (20%): This group will further divide:
     • Basic Paid (15% of total users): Assume they use a portion of their 2TB plan, e.g., 100GB per user.
     • Professional/Business (5% of total users): Assume higher usage, e.g., 500GB per user.

2. Calculation:

   • Free Users: 300M users * 0.80 * 1GB/user = 240,000,000 GB = 240 PB
   • Basic Paid Users: 300M users * 0.15 * 100GB/user = 4,500,000,000 GB = 4,500 PB
   • Professional/Business Users: 300M users * 0.05 * 500GB/user = 7,500,000,000 GB = 7,500 PB

3. Total Storage: 240 PB + 4,500 PB + 7,500 PB = 12,240 PB.

This estimate suggests Dropbox stores in the range of tens of thousands of petabytes.