Is there any potential for growing a user base for a product that is:<p>* A visual layer of communication on top of Facebook, thus relies on a mass of users to create traffic.<p>* Browser extension (desktop and some mobile browsers such as Yandex)<p>* Taking into account 75% of users are using mobile devices:
https://www.statista.com/statistics/380550/share-of-global-mobile-facebook-users/
Maybe, but it would be entirely dependent on the good will of Facebook, and you would gave to continuously react to the whims of Facebook's engineering dept as they change their website. Neither of those are going to be acceptable in the long term.
Why would you need a messaging service on top of a website that already has a messaging service?<p>Also, most mobile users can't (or don't know how to) install mobile browser extensions.