We define a monthly active person (MAP) as a registered and logged-in user of Facebook, Instagram, Messenger, and/or WhatsApp (collectively, our "Family" of products) who visited at least one of these Family products through a mobile device application or using a web or mobile browser in the last 30 days as of the date of measurement. The numbers for MAP do not include users on our other products unless they would otherwise qualify as MAP based on their other activities on our Family products. We do not require people to use a common identifier or link their accounts to use multiple products in our Family, and therefore must seek to attribute multiple user accounts within and across products to individual people. Our calculations of MAP rely upon complex techniques, algorithms, and machine learning models that seek to estimate the underlying number of unique people using one or more of these products, including by matching user accounts within an individual product and across multiple products when we believe they are attributable to a single person, and counting such group of accounts as one person. As these techniques and models require significant judgment, are developed based on internal reviews of limited samples of user accounts, and are calibrated against user survey data, there is necessarily some margin of error in our estimates. For additional information, see "Limitations of Key Metrics and Other Data" located in the Appendix of this presentation. In the second quarter of 2020, we updated our Family metrics calculations to reflect recent data from a periodic WhatsApp user survey and to incorporate certain methodology improvements, and we estimate such updates contributed an aggregate of approximately 50 million MAP to our reported worldwide MAP in June 2020.
