I'm honestly not sure if you implicitly meant that these other apps are popular/used - which would be valid, but I guess we'd need to get the market share #, or

I'm honestly not sure if you implicitly meant that these other apps are popular/used - which would be valid, but I guess we'd need to get the market share #, or if you are asking strictly based on the presence of competition. Monopoly is defined by market share in a specific regions, not by the unavailability of alternatives (1). So it doesn't matter if there are "many other messaging apps" what matters is what's being used. (1) https://www.ftc.gov/tips-advice/competition-guidance/guide-antitrust-laws/single-firm-conduct/monopolization-defined https://www.ftc.gov/tips-advice/competition-guidance/guide-a...