i might actually argue that a lot of what happens on the internet nowadays ought to be nationalized. and, what does that mean?
well, what does facebook do? it's kind of a personal web space. what the ubiquity of facebook really demonstrates is that people want a little space on the internet that belongs to them, where they can post their ideas and interact with their friends - and that they don't want to pay for that space. while facebook makes a lot of money on advertising, most users that know how to install ad blocking software do so as soon as they know how to. if nationalizing facebook eliminated the advertising motive, it would solve a lot of the data concerns by means of decommercializing it. i mean, a government might have reasons to store your data, but making money wouldn't be one of them.
now, somebody might argue that they're afraid of censorship if the government were to take over facebook, but this is actually completely backwards. if facebook were actually a government owned service, you would actually have free speech rights, and any kind of censorship could be dealt with via lawsuits. right now, the fact that facebook is a private server means it's users don't actually have free speech rights at all. while i'm not really concerned about data collection, strengthening speech rights for facebook users is something i'd actively support.
facebook has, in fact, faced competition. it defeated myspace, and then defeated google+. in both cases, the primary reason that the competition lost was that users wanted to be involved in the biggest network. if the idea is that no competitor exists because facebook is stifling it, i question that logic. it's actually very hard to come up with any kind of benefit that would follow from introducing competition into the social network "market", and even trying to understand it in these terms is really demonstrating a lack of understanding of what it is. it would make far more sense to consolidate all of the networks into a single service - and any attempt to fight against this is ultimately a fight against overwhelming user preference.
likewise, imagine walking into a library and being given the option to choose between competing catalogue systems. you'd quickly go mad - you wouldn't know where anything was. and, while there is currently a competition underway between the dewey decimal system and the library of congress, anybody who's dealt with this knows how frustrating it is. i can imagine no benefit whatsoever in creating competing search engines...
what would be a step forward, though, would be to standardize it. how free is the google search algorithm, really? and, as it has a commercial motive, the results are often somewhat broken. for example, google has for years resisted attempts to remove sites from it's results, fully aware that it would mostly be used to remove commercial websites. the result is that searching for actual, useable knowledge takes a lot longer than it should, because you have to sort through hundreds of people trying to sell you something, first. if nationalization would change the purpose of google's search from trying to sell you something to helping you find information, that would be something i would actively support.
i really have less to say about amazon. unlike facebook & google, amazon doesn't provide for any useful service that people actually want, but is simply a store. on the one hand, i don't really know what the purpose of telling people that they have to buy their food from a different website than their books is. on the other hand, i don't have any real aversion to splitting them up, either. this strikes me as an expensive and frustrating triviality. amazon also has all kinds of competitors as it is, so the idea that they're a monopoly is off the mark. personally, i rarely use it because it doesn't take paypal.
i don't expect people to react well to her proposals, but perhaps a broader discourse around what kind of public policy we should implement here is welcome - and my vote would be to nationalize them, rather than to break them up.