The core premise of BrowserBox and Mighty is similar - virtualize and run browsers on the server. Mighty is desktop app meant for end users. BrowserBox's API is for developers who can integrate it into apps or build custom apps using the platform. In the long run, one can potentially build a Mighty like app using BBX APIs. It is still early days and looking for active feedback from the community to see where it can go.
At its core, the essential work is to detect changes important to the user. Adding summarization techniques to further weed out the noise would be a very important improvement.
Thanks for your kind words. The stack is a mix of both. Browser runs on the server and sends updates to the client via websocket. Then it is painted on the client. On the client-side a part of noVNC js library is used to capture input and is sent to the browser running on the server.
Getting started would certainly be much simple when using screenshot or page HTML for comparison. Sieve could do that too! More work needs to be done to make startup faster.
On the other hand having filtered text provides multiple advantages. The filtering becomes accurate. It can be used to compute rules to take conditional actions. Notifications delivery via email and SMS would make more sense as well.
Running a browser on server enables another cool function. User could record macro and run the macro when text satisfied a pre-condition.