janrain.comは安全ですか？

From their site: "Collect, store and leverage user profile data from social networks..." Any body that actively collects information from a persons multiple login data can link usernames and e-mail addresses with profiles, comments, searches, what you read, buy, watch, who you contact, your friends, your comments, tweets, and eventually know your identity, your details and your friends. This type of activity can potentially be very dangerous to the user. Always use different usernames and passwords and, if possible, a couple of different e-mail addresses. Do not use single login to access different sites, especially social networks, webmail and searches.