Thanks for the great feedback. :)

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.

Edit: typo