Normally, I would ignore anyone who didn't realize that a comment modded +5 Funny was in fact a joke, not intended as a literally true statement. But first, you're wrong in interesting ways. I mean that as a compliment--people who are right or wrong in uninteresting ways are so boring as to be de facto nonentities, and people who are right in interesting ways are exceedingly rare. Second, you express yourself coherently. I therefore deem you to be worth talking to.
Let's deconstruct my joke. In actual fact, France's influence is larger but declining, while Twitbook's is smaller but increasing. Claiming, facetiously, that those trends have gone so far that the situation has reversed emphasizes the trends themselves. It's a statement which is literally false, but in a way that highlights something true. That's something I (and apparently several people with mod points) find funny.
But we do actually disagree--you think I was overstating the influence of social networking, but I was actually understating the influence of France. Social networking, especially Facebook and Twitter, are a much bigger deal than you claim they are. Point by point:
It doesn't really alter people's values
There has been much discussion, including here on Slashdot, about the effect cable television and the internet are having on people's political views. We can, more and more easily, choose to avoid exposure to differing viewpoints. This positive feedback loop seems to be leading us to hold more and more strongly to more and more extreme positions. I'd call that an alteration of our values. Social networking is not the driving force of that change, but it's certainly a factor.
Just as widely discussed is the rapid, universal devaluation of privacy--primarily and directly due to social networking. Whether that's a good or bad thing is far from clear, but it's definitely a big thing.
it doesn't lead people to do anything new ... it's a different way of doing the same thing
The big new thing that Facebook does is that we no longer have to consciously choose to keep in touch with casual friends--we have to consciously choose not to. I'm Facebook-friends with dozens of people I went to high school or college with but haven't seen since graduation, former coworkers, siblings of friends, etc. These continuing relationships are not a big part of my day to day life, but any of them could be rekindled--if we move to the same city, or one of us posts about a common interest we didn't know we shared. That's something that was never possible before, even with earlier social networking sites. Nothing before Facebook had a large enough userbase to have that effect.
You can break all forms of communication down into four categories: one-to-one, one-to-many, many-to-one, and many-to-many. A conversation in person, or a personal letter, is one-to-one. The written (published) word (or television or pretty much any form of artistic expression) is one-to-many. Democracy is a kind of many-to-one communication, as is survey-based research. But many-to-many communication never existed before the internet, and you could almost use it as the primary distinguishing characteristic of social networking. Social networking is the subset of internet activity that is not just a faster version of traditional one-to-one or one-to-many communication. The major breakthroughs of the other three categories are language, democracy, and the printing press--it's an understatement to call them world-changers. We may not know yet HOW many-to-many communication will change the world, but there's no doubt that it's going to. Check out the last three paragraphs of this speech by Douglas Adams for a somewhat more in-depth discussion of this idea.
Twitter is drastically different from anything else that exists on- or offline, including other social networks. All other forms of socialization can be modeled by simple graphs--individuals are vertices, with an edge between people who know each other. Twitter is a directed graph--Alice can follow Bob, Bob can follow Alice, or Alice and Bob can mutually follow each other. This is a radically new idea.
it has influence only on individual small groups ... I realize there are a hundred million of such small groups, but they don't represent one gigantic culture
Yes, they do. By definition. The thing you're missing is that those groups overlap--you can play Six Degrees of Kevin Bacon to connect any two people. Alice knows Bob, Bob knows Carol, Carol knows Dave, Dave knows Elizabeth, and Elizabeth knows Frank. Even though Alice has never even heard of Frank, they're part of the same culture because of that chain of connections. There's nothing more to culture than the cumulative behavior and communication of an interconnected web of individuals. You basically just said "(definition of term), but that's not (term)."