Google could also block any facebook links from appearing as google search results if things become more tenuous. I highly doubt this would ever happen since they might face a heavy duty backlashing, but the thought is intriguing.

Facebook is not really optimized for SEO (walled-garden), so this would not be the strategic crowbar to their kneecap.

IMHO, the better solution would be to blacklist all associated Facebook IP addresses and domain names from the Android OS.

Blacklist all Facebook IPs on Android? Haha, that's some heavy warfare you're talking about and I don't think the users will like that either.

Either one would cross the line very quickly into anticompetitive behavior.

Facebook could block all users that have an @gmail.com email address. I think Facebook has the bigger crowbar.

I do agree. Some people have referrer turned off, but afaik, they are the minority and this should do the trick. Google surely though about it.

This also works the other way. If you rely on FB assets (images, ...), they can shut your access down immediately the very same way. Can't say I like it.

I'm pretty sure Facebook would then remove the href on the link & tell people to copy/paste it into their browser.

Or just put the link on a HTTPS page as referrer information isn't sent from those.

Google could also make an API requiring an API key to access it (for services/tools that depend on it). Refuse to give Facebook an API key, and allow apps that depend on the current method to transition. Within 30 days or so, shut down access to it via the predictable URL and make it some crazy URL when they request it.

You do know the referer header is optional don't you, I mean, you'd look pretty dumb relying on it for any web service because, you know, some crazy people turn them off altogether, perhaps with the Firefox add-on RefControl.

You're missing the point. It's not about disallowing importing the address book from Gmail to Facebook, it's about making it more difficult in order to force Facebook to offer reciprocity.

You will always be able to export the CSV version of your Gmail address book yourself and feed it wherever you like. It's just slightly less convenient and the experience is not so smooth anymore.

I'm so glad someone understands.

What does that have to do with http referer headers ?

I have seen various websites which use referrers despite this drawback. They will simply block you if your browser doesn't send a referrer.

Do you know any off hand ? I've had referer headers stripped for a few months now and afaik it's never caused my any problems.