front end can be
1. an iphone app, gphone app, blackberry app, kindle book, nook book, or any other mobile reading device.
2.web browser such as IE, FF. depending on what client is, show different layout for that browser so it gives good comfortable user experience.
--however, to make money, any front end will display ad. because ar/10k is free, u just cannot make money from selling the front end
1. read xbrl from sec
2. save into db.
3. serve the reading request from front end
4. registration service so user can save their reading and seamless switch among any device.
java, tomcat, mysql