There is a point that hasn't yet been mentioned here about the fundamental difference between an address book, and Facebook.
Facebook is okay to be a dead-end for contacts' emails, since the email upload is used once to find others on the service. After that, if you need to contact someone else on Facebook, you can do so with a wall post or an inbox message. The email address is irrelevant.
With an address book, you need it to be portable, since the medium is accessible from many different locations and services.
The fact is that you dont need to get your friends' contact details out of Facebook. You sign up for Facebook to make Friends on Facebook and communicate over Facebook. Not to communicate over email, etc. (And certainly not over a rival network.) When you add someone to your address book, you do so to communicate with them over email, or phone, or whatever, which are inherently completely open and interconnected systems. [Surely there is a debate to be had here about the ubiquity of Facebook as a platform and that it should be open - could you imagine Facebook Clients? But I dont believe that's a debate about exporting existing contact info.]
To that end, Google warning users about the terminal nature of their exported data is unnecessary and only confuses the process of finding friends for users (who, by the way, aren't thinking about data portability, or building up an address book/contacts list on Facebook, they're thinking about making Friends on Facebook, to communicate over Facebook)
TL;DR: This whole mess doesn't matter, and Google is only making things complicated for users.
You don't need to use the email upload once either. That's the point. Google's making it clear that you getting something from them "for free" and you won't be able to go back in the future.
>The email address is irrelevant.
I disagree. My usage pattern is to use facebook to find a person, then get their email and contact them through email, since I check my email more frequently than I do my facebook. (which is almost never, since I have it send me anything important by email.)
Sure. But then Facebook doesnt really have a reason to care about you, as a non-user of their service, and keeping data locked in is their best way of keeping you coming back.
Facebook is okay to be a dead-end for contacts' emails, since the email upload is used once to find others on the service. After that, if you need to contact someone else on Facebook, you can do so with a wall post or an inbox message. The email address is irrelevant.
With an address book, you need it to be portable, since the medium is accessible from many different locations and services.
The fact is that you dont need to get your friends' contact details out of Facebook. You sign up for Facebook to make Friends on Facebook and communicate over Facebook. Not to communicate over email, etc. (And certainly not over a rival network.) When you add someone to your address book, you do so to communicate with them over email, or phone, or whatever, which are inherently completely open and interconnected systems. [Surely there is a debate to be had here about the ubiquity of Facebook as a platform and that it should be open - could you imagine Facebook Clients? But I dont believe that's a debate about exporting existing contact info.]
To that end, Google warning users about the terminal nature of their exported data is unnecessary and only confuses the process of finding friends for users (who, by the way, aren't thinking about data portability, or building up an address book/contacts list on Facebook, they're thinking about making Friends on Facebook, to communicate over Facebook)
TL;DR: This whole mess doesn't matter, and Google is only making things complicated for users.