They seem to do a lot of serious damage, and not much good -- they do provide *some* people with a harmless outlet for their cat photos or their knitting algorithms, but generally, they seem to spend a lot of time inflicting damage on the culture.
How would you do that, get rid of them? Quite simple, really. The US has two kinds of "media" -- non-social, in which the owners are responsible for content; and social, which are really derived from old laws primarily dealing with telephones, which held that the phone companies weren't responsible for what people said on their system. Facebook and other media companies managed to get themselves classified under the telephonic laws, so that it Person A libels or slanders Person B, well, it ain't *their* fault. Bullshit. Facebook ain't a telephone. In my view, people who are libeled or slandered on it should be able to sue, just as they can sue a newspaper or a network for a content that appears on those media. Simply reclassifying the would require that Facebook get really serious about monitoring their forums, or get driven into bankruptcy with thousands and maybe tens of thousands of lawsuits. I think the reclassification would eventually cost Facebook a ton of money, but so what, not my problem.