Do you use Facebook? Do you love to like? An experiment requesting users to like their page and then getting a free coffee as a reward show that a lot more information can be gathered.
Your address, date of birth, mother's maiden name, workplace, and a lot more pieces of information are accessible.
Watch the results of the experiment at: https://www.youtube.com/watch?v=sq-0tjv4_BA
Always remember that nothing is unhackable, and there have been numerous hacks on social media sites. The golden rule of privacy is if you wouldn't put that information on a public billboard, don't put it on the internet.