 When SNS in particular are considered in light of these questions, some distinctive considerations arise. First, sites like Facebook and Twitter (as opposed to narrower SNS utilities such as LinkedIn) facilitate the sharing of, and exposure to, an extremely diverse range of types of discourse. On any given day on Facebook a user may encounter in her NewsFeed a link to an article in a respected political magazine followed by a video of a cat in a silly costume, followed by a link to a new scientific study, followed by a lengthy status update someone has posted about their lunch, followed by a photo of a popular political figure overlaid with a clever and subversive caption. Vacation photos are mixed in with political rants, invitations to cultural events, birthday reminders and data-driven graphs created to undermine common political, moral or economic beliefs. Thus while a user has a tremendous amount of liberty to choose which forms of discourse to pay closer attention to, and tools with which to hide or prioritize the posts of certain members of her network, the sheer diversity of the private and public concerns of her fellows would seem to offer at least some measure of protection against the extreme insularity and fragmentation of discourse that is incompatible with the public sphere.