As the feed name suggests, top stories feed shows the questions with most answers to the user. And it removes the questions from the feed which have been passed by the user. 

Yes, email alerts are sent to appropriate users. As example, below are few such cases though there are more scenarios in which emails are sent.

• When a user is asked to answer a question
• When a user received a message
• When a user is followed by anyone
• Comment is made on a question user is following

How to undo Anonymous answer?

This is the best way to grow

don't know

Here is the changelog (as on February, 2019):

Version 1.8.1 (17th Jan, 19)
* 3 default feeds (top, latest and unanswered)
* Admin can remove topics
* Links inside questions and answers open in new window
* Bug fixes

Version 1.8 (7th Jan, 19)
* Admin Settings
* Mailchimp integration
* Auto tags
* Bug fixes

Version 1.7 (10th September, 18)
* Design improvements
* Bug fixes

Version 1.6.5 (29th August, 18)
* Installer changes

Version 1.6.3 (14th Dec, 17)
* Support for comments moderation
* Bug fixes

Version 1.6.2 (2nd March, 17)
* Bug fixes

Version 1.6.1 (15th Feb, 2017)
* Bug fixes

Version 1.6 (1st Feb, 2017)
* Unified ajax search for users, topics and questions
* Bug fixes

Version 1.5 (23rd Jan, 2017)
* Verified profiles (New Feature)
* Login with Google (New Feature)
* Choose topics for new users (New Feature)
* Social sharing links for answers (New Feature)
* Bug fixes

Version 1.1 (12 Jan, 2017)
* Performance improvements
* Bug fixes

Version 1.0.1 (10 August, 2016)
* Bug fixes

Version 1.0 (1 August, 2016)
* Released