> Of course, there's a question about how we define "monopoly": there's a lot of counter-arguments to this, and a lot of them perfectly valid. There's Twitter, there's self-hosting, there's all these forums around the internet... But at the same time, isn't it strange that "monopoly" as we understand it is a binary category? I think it's reasonable to think about it as a continuum; and Facebook today would certainly be very far on that axis.
Interestingly, Charles Munger has spoken quite extensively on how market dynamics can often favor consolidation and "winner takes all" phenomena such as the Facebook example you describe. Indeed, he discusses newspapers as follows:
"The most obvious one is daily newspapers. There's practically no city left in the U.S., aside from a few very big ones, where there's more than one daily newspaper. And again, that's a scale thing. Once I get most of the circulation, I get most of the advertising. And once I get most of the advertising and circulation, why would anyone want the thinner paper with less information in it? So it tends to cascade to a winner-take-all situation. And that's a separate form of the advantages of scale phenomenon."
Similar things happen with the Internet. Indeed, I find it extremely surprising that anyone would think that the Internet would be different in this respect.
> After disabling my Facebook account for half a year, it became painfully evident that I wouldn't be able to keep in touch with a lot of family and friends without it.
There were methods to keep in touch with family and friends before that have not gone away. Anyone who I regard as a close friend would certainly understand when I explain to them why I don't use Facebook and how to contact me (via email, etc). Maybe this is a bit harsh, but for me if someone I know does not understand this and spend the minimal effort to contact me via other channels, after I explain to them in copious detail, I don't bother keeping in touch with them.
As for business stuff, this is where the centralization does get annoying. For instance, for a musician these days it definitely helps to have a Facebook and/or Twitter account and/or YouTube channel. On the other hand, the music industry has been plagued by these issues for a long time - before it was the album makers as the gatekeepers, now it is Apple with iTunes, Google with YouTube, etc. Most of what has changed are the names of the gatekeepers and means of distribution, not their existence.