SHOW IH: arandomquote.com Great books summarized in 5 quotes. Question about mailing lists

This project born because I love books and when I read I like to take notes and save quotes that help me to remember the key points for that specific book.

In the main page there is a list of all books http://arandomquote.com also you can get a compiled list of all quotes by category for instance business quotes: http://arandomquote.com/categories/business/

Another feature, you can play a simple game to guess the author of a quote. http://arandomquote.com/guess/

I will try to add amazon affiliate links this month.

My question is should I implement a mailing list? it's so what could I offer? weekly updates? random quotes? recommended books? What services do you recommend?

thanks for the feedback.