"When you think about it, Facebook is a closed system." People say this all the time without any justification. As far as I know, all content within Facebook t

"When you think about it, Facebook is a closed system." People say this all the time without any justification. As far as I know, all content within Facebook that has no privacy restrictions can be viewed without being a Facebook user. Facebook has an API that can be used to both read and write. Facebook is stingy with phone numbers and email addresses, which is a significant failing in my opinion. Other than that, I can't imagine a more open social network that allows users to control who can see their content.