On this age, people are willing to read online rather than going to a library and buying a book. It is way easier and cheaper; thus book publishers should be aware of the importance of both physical and online sales. Also, copyright might be easier when you book in online; they should check the regulations for protecting their work.
Making a SWOT analysis would help to have an specific context con the situation, the good on the tendencies and the aspects that need to be taken cared of.
Strengths:
With online selling on books people would have easier access to the books they want, a cheaper way of reading and instant access to the promotion of new books.
Weaknesses:
Not experienced book publishers, will need time an money to adapt their industry to this new tendency.
Opportunities:
By marketing, they can get to the specific audience who would get interested on reading a book. Little video for introducing the story would be a new resource for making people read.
Threats:
Not having a correct manage of the publishing, may cause online users to copy the publications and getting the credit, as well as online transactions may not be as secure as physical ones.