Facebook has a double role when it comes to existing policy: as a driver of change or of conservation.
On the one hand, Facebook is the primary vehicle for very populist ideas. It sometimes looks like a repository of the worst human feelings: garbage tends to spread virally. In this sense, it can be seen as a help to the established power in keeping people busy with the illusion of participation, by letting them rant freely about flat earth and therefore acting as a safety valve to prevent actual changes.
On the other, Facebook offer an alternative platform to mass media, allowing outsiders to have a voice and augment their reach. It is a formidable tool to bypass the filtering of the media conglomerates, and to let ideas circulate more freely. Indeed, one question is the very definition of populism. According to some, Universal Minimum Income is a populist idea; according to others it is a revolutionary idea.
In other words: would Andreotti (the Italian politician in power for over 50 years, the ideal-type of the establishment) be worried or comforted by Facebook?
But there is a third option. That Facebook acts as a learning platform for people to discover public engagement over time. That it acts as a force of conservation initially, but as a force for change in the medium term.
In fact, I found the same question many years ago when researching the history of philanthropy in the 19th century: one the one hand, it acted as a safety valve for the bourgeoisie and women to be active in public issues without troubling the establishment, on the other, it acted as a stepping stool towards democratic participation.