At my company, we have a place called Quarantone, where people can go not to be disturbed for a couple of hours, that aside, if you are at your desk, it generally means that contact is fine :)
That seems like a good compromise. But then you need quite a bit of spare room in the office dedicated to your "Quarantone". That can be quite hard to find if depending on where your company is located.
That's basically my #1 problem where I work: we're in big open-spaces and you get interrupted all the time. Sometimes just having someone talk next to you can be enough to break your train of thought.
That being said, I agree it's very helpful to be able to talk in person sometimes. I think the solution is just something hybrid, you work remotely a certain portion of the time and get to the office for the other days.
I would be interested to hear yahoo's reason for giving up on remote work though. This article is a bit unsubstantial.