Following on Facebook?

[Snowflakehead ツ]

Just wondering what following someone on Facebook means and how can people that I don't even know follow me? What part of my information can they see?

[Janmejai]

If you are following someone you will get updates from them in your Facebook news feed based on different settings firstly you will only see public updates from them secondly if you are subscribed to their all updates you will also see the posts on which they comment or like.
Their is no limitation on who can follow you.
Your Followers can only see public information which is visible to everyone on facebook(it depends on you that what type of information in your profile is public means visible to everyone).