Service's rights to user information and user's data, user's possibilities to remove or move data back from service
free, freemium, advertising, non-profit community, estimate of service's continuity
published data breaches, location of information, technical implementation, collection of user information
a dedicated user account needed in the service, forced use of third party accounts (Facebook/Twitter/...), possibility of strong or multifactor authentication, possibility of anonymous use, possibility to remove user profile
multilinguality of the service, support and user documents and functionality of support