Yes, that is my point. Abstracting away SMS vs. email is an interesting intellectual exercise, but it doesn't solve any user problems. The sender is the best judge of what transport to use. It's unfortunate, but it's the way the world is today.
You're saying it as if it's a bad thing.
Email is asynchronous. IM and SMS are disruptive.
And on IM versus SMS, the sender of a SMS usually doesn't know if the recipient received the message, while the default behavior of IM is to notify your contacts list if you're online.
These are different mediums people use for different kinds of communication / contacts.
But I don't expect Facebook to get this, especially considering their total disregard of the way people interact with one another. It's a wonder they are number #1, but I guess the alternatives sucked a lot more.
But yes - different methods of communication have different semantics, as Marshal McLuhan never said. But it is nice to group them, and to be able to seamlessly transfer between them. No doubt I'd love Google Chat's "This person is now offline. Click here to send a SMS" if they had any support for anywhere but the States. And I look forward to the Sense UI concept of crossing the streams coming to stock Android so I can use it myself.
It depends on the carrier and on the sender ... most people don't get delivery reports back.
> Email, by contrast, hasn't got any reports that any decent human being would use
Yes it has, you can embed tracking pixels in it. Not really reliable though.