As the success metrics for Facebook's enterprise chat application, I would propose the following: 1. User Adoption: The number of users who have downloaded and installed the app, as well as the number of users who are actively using the app on a regular basis. 2. User Engagement: The amount of time that users spend on the app, the frequency with which they use it, and the number of messages that they send and receive. 3. Customer Satisfaction: The level of satisfaction that users have with the app's features, ease of use, and overall performance. 4. Revenue: The amount of revenue generated by the app, either through direct sales or through advertising and other monetization strategies. 5. Market Share: The percentage of the enterprise chat application market that Facebook's app captures. By tracking these metrics and analyzing the data, we can determine how successful Facebook's enterprise chat application is and identify areas where improvements can be made.