Whether you want to sign up with social media site or recruitment site or a job site, you will always asked to give your personal information. If you are not very comfortable in giving away you personal information, you can just do one thing, instead of sharing your information on every site you join, share your information on just one site and share link from that site on other sites. For instance, instead of giving out your personal info on freelancing sites, you can share links to your Facebook or LinkedIn profiles. By the way, how comfortable are you about giving your personal information.