Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
Q&A for work
Connect and share knowledge within a single location that is structured and easy to search.
So, 3rd party applications will be able to notify users about new answers and comments.
API V2.0 introduced the /inbox and /inbox/unread routes.
They provide read-only access to a user's inbox, and both require authentication.