You raise a valid question, and real-world networks/clubs that users pay for and derive much of the same benefits as Facebook are very well-entrenched as justif

You raise a valid question, and real-world networks/clubs that users pay for and derive much of the same benefits as Facebook are very well-entrenched as justified expenses, e.g. Country Clubs, Fraternities. but is it reasonable to understand that users would oppose paying for the kind of value that Facebook offers? Yes, absolutely. The sentimental and communicative value it provides really is quite fervent, but I think we have a long way to go to evolve into a culture that will pay for something that, in the realm of social interaction (not including dating), is intangible, not physically interactive, doesn't provide us income, and can be had for free (emails/phone calls/picture exchanging), simply for the convenience it provides. Sure there are exceptions and maybe if Facebook charged from the beginning, the prospect of Facebook charging for its services might not seem so outrageous, but, for the average user, the contrast of how removed facebook's value is from our everyday physical life in contrast to how "physically" money exists in the real world I think explains this opposition rather well.