Almost every transactions now are done via social networking sites, emails and eshops over the web. If you don't have an access to your email (or facebook) it is either you still make use of your snail mail or connect via phonecalls (if you're rich enough to afford load for your celphone).
Good thing facebook email was invented. It sounds cool to me because if you're hesitant to use your personal and work email due to privacy purposes, you can give them your facebook email as an alternative. But don't ever use it as a professional or work email. Don't use a username like sweetsexybiatch. People will not find you serious enough for your job.Also you can try to use a different email for social networking and the one you use for work and professional purposes. You can sign up in Google, it's free. *wink.