User has to be authenticated in order to see and contribute to the translations
a) Make dashboard (list of books and translations with statistics) available to anonymeous users
b) Maybe allow anonymeous users to start translating blank chapters (but don't save it)
Signup:
a) Fields: username, e-mail address, password, password confirmation (all required)
b) E-mail confirmation (required for authentication)
c) Login with username or e-mail address
User without postal address
a) can edit translations (change up to 50 % of a [calucated] completed paragraph)
b) can translate new paragraphs if he types slow enough
c) cannot gain reputation
d) has to enter the postal address after logging in 20 times or after 40 weeks (i.e. when he feels comfortable with the site/I forgot the other nice formulation)