I like the idea - let me challenge it:
1) How does it compare to Google News Alert?
2) Can I modify sources, e.g. add/removing?
3) Can I modify frequency of email sending?
2) Can't modify the sources, the system actually has no concept of a "source". However, you can modify the topics you follow.
3) Yes, you can modify it to be real-time, based on sentiment or volume of discussion changes. OR you can set it to be time interval based.