• Make sure your Facebook app doesn’t have microphone access.
• Better yet uninstall Facebook app from your phone

Why? I have heard of situations where two friends talk about a car and then facebook started showing them ads about that car.

• Facebook has close to 2bn users, posting over 100bn things each day.
• The latest numbers can be obtained from https://investor.fb.com/financials/default.aspx → choose the latest quarter → Earnings Slides.
  • The Q3 2020 pdf → slide 2 shows
    • The number of daily active users (DAUs) for the past 9 quarters.
    • In each quarter, the numbers are broken down into four regions.
    • For each quarter, it also shows the ratio of daily active users to monthly active users.