I'm sorry, but you generalized about the same billion people and even offered a completely imaginary 90% statistic to boot. And I'm not an outsider, not to the industry, not to web services, not to social networks, not to FB itself. I've been a user and an employee and a consultant for all of those things.

And what exactly do you think you mean by "I think we're reaching the limits of the English language with that one."? The semantic "limit" of the 3rd person plural pronoun is that there is an explicit or implicit, antecedent substantive referent. Your nonsense compounds itself.

"Indispensably useful" has positive connotations, yet most people I speak to (even outside the HN/tech crowd) do not speak of Facebook in positive terms.

Some use it simply because it's addictive. They don't want to use it, they don't enjoy using it, but they're eventually drawn back in after trying to quit. In this sense, it's "indispensably useful" in the way crack cocaine is indispensably useful.