I always warn my kids that sarcasm (our family's primary humor) doesn't translate to the Internet, but you obviously heard it in my voice.

I'm not a Facebook hater or a Facebook fan ... plenty of my friends are there, but there are hundreds of other ways to keep in touch with them (Jabber is everywhere). In any case, Facebook and to a large degree GMail are just not relevant for me. If they weren't there, or I felt compelled to abandon them for some reason, I wouldn't have a problem finding another way to contact them.

So let's recognize that Facebook, Google and even Microsoft are young in comparisons to the average human's life-span. And when the next big thing comes along, we'll embrace it until temporarily too.

One big caveat ... these companies build up customer good-will over longer or shorter periods of time and can persist until that reservoir is run dry. With a little care, that good-will can last a long time, so I'm not saying that Microsoft is in any danger as a company. But I do think they're past their heyday and will have to reduce their margins to keep business.

Anyway, we're so conditioned to sign-up for a service at the drop of a hat that these services become "cheap" to us. They didn't cost us anything and they don't cost much to throw away. Look at the number of people who signed up for Hipster without knowing what it is. I think everything you've written is true EXCEPT, I suspect it's more common for users to simply abandon an account without closing it. I'd love to know what Facebook's churn is.