@elizafox past a certain size a site becomes effectively a public place and it changes the nature of the appropriate moderation of said site. Otherwise you end up with an Occupy Wall Street/Zucotti Park almost ancap situation where there is nowhere to effectively mount protest where you can be seen that isn't whim to private interests. I believe Facebook meets this criteria. The mechanisms by which is shows or does not show content should be known and auditable. It is in the public interest for the moderation to be known and public have input.