Can PeepSo users follow certain categories of questions like in Yahoo Answers?
Yes. Your site users can subscribe to certain question categories and follow questions and answers within that category or categories through their profile.
To learn more about this feature see this Help article.
I would like for a post to automatically post to the Users wall whenever they ask a new question. Can the add-on do this?
Is there any way to customize the Post that is automatically posted whenever a user asks a new question?
The Post Template can include some shortcodes to make the post content nice and relevant to the question.
To learn more about customizing activity posts see this Help article.
What is the Benefit of this add-on?
Can your add-on automatically post some activity on the Users Feed when they Answer a question?
Yes. As well as posting on their feed when they ask questions there is the option to post activity on their feed when they Answer questions too.
To learn more about automatic activity posting see this Help article.