facebook.comは安全ですか？

If you're not careful with your information, it will be used by third party companies who then use that to try and get your friends and family to participate in their software in the hopes of compiling more information on everyone. What they can do with that information is vast, so keep an eye on what information you provide, and who gets to see and use it.

Social networking, sure, however our personal information has often been used in ways we didn't approve of. I also don't appreciate the applications running on Facebook as these may grab my personal info in ways I also don't approve of. There's no sure way to have my personal information deleted if I were to remove my account. In short, I've seen changes made on FB which first engage in misuse and later say "Sorry" —but damage is already done. We're better off running our own e.g. Wordpress sites, if not individually, at least by someone you know and trust. ;-)

Facebook default settings are very unsafe. If you do mobile uploads, your phone number could be published without you knowing it. Many fake apps trying to trick you so they can hijack your profile. I have received friend recommendations from Facebook of 15 yearolds, so not safe for kids. There are apps that show nudity. Although this is against Facebook policies, Facebook fails to remove these apps and images.